It may be possible to greatly reduce iron in pool water

[smallpooldad]

It seems it may be possible to greatly reduce iron in pool water. I look forward to Chemgeek's opinions.

This is of course is extremely:


Experimental


: relating to a scientific experiment or to scientific experiments in general

: made or done in order to see how well something works

: using a new way of doing or thinking about something



So please wait for Chemgeek's remarks, before making any commitment.


Note this was done in a plaster pool using liquid chlorine/bleach, and may not work in an any other type of setup.

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Using the AA process for iron stain removal is good but it does not solve the problem of it returning. Some of Einstein's quotes, which I keep at my desk to control myself, seem as if they might be helpful here in moving the solution along:


Everything should be made as simple as possible, but not simpler

Anyone who has never made a mistake has never tried anything new

Common sense is the collection of prejudices acquired by age eighteen

The only thing that interferes with my learning is my education

The whole of science is nothing more than a refinement of everyday thinking

The important thing is not to stop questioning. Curiosity has its own reason for existing

Whoever undertakes to set himself up as a judge of Truth and Knowledge is shipwrecked by the laughter of the gods

Insanity: doing the same thing over and over again and expecting different results.

Not everything that can be counted counts, and not everything that counts can be counted

Knowledge isn't truth. It's just mindless agreement. You agree with me, I agree with someone else - we all have knowledge. We haven't come any closer to the truth. You can never understand anything by agreeing, by making definitions. Only by turning over the possibilities. That's called thinking. If I say "I know", I stop thinking. As long as I keep thinking, I come to understand. That way, I might approach some truth

If you are out to describe the truth, leave elegance to the tailor.
On being reproached that his formula of gravitation was longer and more cumbersome than Newton's.

Everyone sits in the prison of his own ideas; he must burst it open, and that in his youth, and so try to test his ideas on reality

It's not that I'm smart, it's just that I stay with problems longer

And from a very successful German businessperson

Other people have smart children to


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By pure accident I ran across this idea after I discovered a jug of "PHOSfree Commercial Strength", manufactured by "Natural Chemistry" in my garage storage. I have used it before for orthophosphate removal, but as orthophosphates are not a major issue according to this forum, I forgot about it. As I had a jug I thought I might as well use it, the clouding effect was not an issue in the past, it cleared up in about 24, sometimes 48 hours, and filter blockage was not too bad. To be extra careful before I used it I "Googled" the MSDS, see here:

http://naturalchemistry.com/get_fil... English MSDS - Jan12.pdf&name=PHOSFREECOM-EN

It states that the main ingredient is "Basic aluminum chloride" with Acid, known commonly as a PAC (PolyAluminum Chloride). I then "Googled" "aluminum chloride waste water management" and "aluminum chloride boiler treatment". It was very interesting to note that it now used in preference to Alum for removal of not only orthophosphates, but also heavy metals (iron being one of them), and silica. Many other items are also removed among them organic contaminants, nitrates, and others. It seems it is used heavily in the production of high grade Muriatic Acid to remove contaminants, mainly heavy metals.

Silica in the water supply on Oahu, not the other islands as their water is primarily from streams and rivers, is about 50 ppm in the municipal tap water, obviously a major staining issue. Our water comes from ancient volcanic aquifers under the surface of Oahu. These high ppm are also true for other parts of the US notably, California's Central Valley area around 60 ppm, and many areas of Texas where the ppm range from 38 ppm, to as high as 100 ppm in a few area. I got rid of my silica staining on the walls using the Hydrogen Peroxide method in conjunction with an Ascorbic Acid (AA) treatment of 1 lb, but I needed 4 times as much HP as I mentioned in my previous post on the subject, there was literally a little beach of sand both light colored and orange colored sand/crystals at the bottom of the pool after draining.

The interesting thing here is that my own experimentation experience deviated greatly from the amount that boiler cleaning papers mention for removing both calcium carbonate and silica scaling. This is most likely due to the fact that they do it on a regular basis, so there is less to remove, and I did it for the first time in 16+ years, thereby requiring 4 times as much Hydrogen Peroxide to do the same job, although the Ascorbic Acid required was the same being only one pound for 10,000 gallons.

Silica in most US areas averages around 8ppm to 16 ppm, not a real staining concern for the first 6 to 10 years. Often on this forum I will read that the Vitamin C tablet did not work, my guess in the absence of iron staining that it is silicate scale which is much harder to remove, and typically cannot be removed with the low pH treatment, although a really aggressive and damaging acid wash might accomplish, this but at what cost to the integrity of the plaster.

The recommended method, it seems, in cold water such as pool water, is first to remove the phosphate at a pH between 7.0 and 7.6. Then to do one or two additional treatments to remove silica and heavy metals (iron, etc.)from the water (not the surfaces), at a pH of 6.8 or below. My second and third treatments were done at a pH of 6.7. And yes I have a properly two point calibrated pH meter (recommended). Using half the jug, for the phosphate removal at a pH of 7.4 (note it seems it cannot remove the last 100 ppb according to the literature I read), then two additional treatments using a quarter of a jug at a pH of 6.7, using Muriatic acid to lower the pH, starting at an alkalinity of around 80 -90 it reduced it to around 50 ppm.

It was further recommended reading the "Googled" scientific papers to add and use a Copolymer to enhance the effect of flocculation, I used Jack's Magic Magenta Stuff, MSDS here:

http://www.jacksmagic.com/pdfs/MSDS-JMMAGENTA.pdf

An "Acrylic Acid Copolymer"

After the first 2 treatment I added an additional 5 oz to my 10,000 gallon pool, after the final treatment I added the recommended higher initial recommended dosage. Ironically the cleaner the pool the high the dosage needed.

Well this was done about 3 months ago, and by keeping the pH at 7.5, and adding a weekly dose of the Magenta stuff (Acrylic Acid Copolymer), my iron problems have gone away. Occasionally I add a little more copolymer if we have had heavy winds (over 26 mph) as it seems to bind any iron deposits on the pool floor.

The papers I read on line stated to use phosphonic acid, such as HEDP (Jack's Magic Purple Stuff) in doses of a minimum of 5 ppm (Jack recommends 12 ppm) in conjunction with Acrylic Acid Copolymer to control iron staining but I can no longer buy the Purple Stuff in my area, the best pool person I know told me he only uses the "Magenta" and it works, perhaps this is why the stores are no longer carrying it. Personally I would prefer both HEDP and the copolymer, but I cannot get it.

Usage Notes:

1. As regards the copolymer "Jacks Magic Magenta Stuff", from what I have read it performs optimally at a pH of 7.5. For waters/pools with very high iron, other heavy metal content, silica, or organic debris, even going triple the dose is not dangerous, as I understand it

2. The Aluminum Chloride does seem to lock up the CyA (Cyanuric Acid) for about 2 - 3 days, by which I mean a 50 ppm level will show if measured a 30 ppm level, a drop of 20 ppm. And indeed the daily chlorine drop will be greater than usual. After 2 -3 days it will again go back up to 50 ppm, and because the pool is a lot cleaner, the chlorine usage may drop.

3. The level of cloudiness that you will incur initially seems to be dependent on both the phosphate level and organic debris in the pool, if you have a lot say 2,500 ppb of ortophosphates , and other organic debris in other words much higher TDS (Total Dissolve Solids) than your salt level would imply then it will be a lot milkier for 24 - 48 hours. If it takes longer do not worry. But measure your orthophosphates again to see if you did bring them down to around 100 ppm, if you did not add sufficient to get them into that ppm area, before doing the last 2 treatments.

Once you get down to 100 ppm the clouding is very little, the next treatment may take only 12 hours to clear. The final treatment maybe only 8.

4. Note of caution: Only Aluminum Chloride based phosphate remover should be removed, NOT "Lanthanum chloride" based removers, such as regular "PHOSfree".

5. If you are going to use a different PAC (PolyAluminum Chloride) from Jack's Magenta Stuff, make sure it can handle high chlorine, over 1 or 2 ppm in this case, as most cannot.

6. Lastly doing this is not inexpensive, but if it keeps lasting and gives piece of mind, and allows one to run at a relatively benign pH of 7.5, it seems to me to be cheap at the price.

Anyway 3 months with absolutely no iron issues is, I believe, a first for me, but am not sure as I getting rather old and my memory is not as good as it was.

It appears that by removing both carbonate and silicate staining with HP and AA from the pool surfaces it helped to avoid iron getting glued/trapped. But the Aluminum Chloride treatment removed iron and silica from the liquid water I believe, and the weekly copolymer treatment (Magenta Stuff) seems to control both iron and silica in the water quite well it seems.

I think this may be worth giving a try if you have heavy iron fill water, because refilling with more water obviously will not help.

Only those of us with long suffering relationships with iron and silica scaling can truly comprehend what a pain it is. Those of you without this ongoing experience/nightmare, or minor experience, this may seem over the top. I realize this. But for me to walk out to a pool where the pH stays at around 7.5 for days on end and have no stains is like Galileo Galilei, knowing that while most of the world thought him wrong, and tried by the Inquisition he knew that by a combination of theory, calculations done by others before him, and experienced observation, and experimentation he was on the right track. Unfortunately he lived out the remainder of his life under house arrest.

So while I will definitely take all comments and perhaps massage the methods, as I did with HP by quadrupling the quantity, based on swampwoman's comment and a personal unsuccessful experience , I will stick with it for now, unless someone comes up with a better method, or chemical(s). Hoping you who read this do not put me to under internet arrest.

Of course the very faint possibility, nay minute possibility, exists that I could be wrong in my assumptions. At which point I will drown myself in a barrel of Chateau Lafite Rothschild, Vintage 1961!




Here are a few assorted articles in no particular order (there are many more), and of course you should "Google" yourself:

http://msdssearch.dow.com/Published...d.pdf?filepath=/609-02022.pdf&fromPage=GetDoc

http://www.polytechnic.edu.na/acade...ts/Activated_Sludge_ChemicalPrecipitation.pdf

http://www.ncbi.nlm.nih.gov/pubmed/21806453

http://www.lubrizol.com/Dispersants...e-of-Polymers-as-Precipitation-Inhibitors.pdf

http://www.sciencedirect.com/science/article/pii/003238619290121C

http://lubrizol.hk/DispersantsWater...luation-of-Silica-Scale-Control-Additives.pdf

http://www.dow.com/products/market/...-2000/?&_suid=1384983647131020523251491788846

http://www.cedengineering.com/upload/Cooling Water Problems and Solutions.pdf

http://books.google.com/books?id=vm...ion water treatment aluminum chloride&f=false

http://www.virginiasemi.com/pdf/siliconetchingandcleaning.pdf

http://www.columbia.edu/~ap2622/pdf/Stability of hydrogen peroxide in sodium carbonate.pdf

http://219.217.227.105:8000/images/...+_enhanced_by_H2O2_at_nature_pHneutral_pH.pdf

http://www.google.com/url?sa=t&rct=...3IDwDw&usg=AFQjCNEbj9pIWp55YW9XCc9qOzE1mJsTBA

 

[chem geek]

Great work! Interestingly, the DIN 19643 standard uses coagulation/flocculation to help remove organics from the pool and they use either aluminum based products (including aluminum chloride) or they use ferric iron products. Their quantity is 0.05 gram per cubic meter (same as mg/L) in weight of Aluminum.

Since CYA is organic it is possible that it partially coagulates with the aluminum, but I suspect it's a weak bond so may just be interfering with its measurement in the CYA test. That would explain why it comes back later since the aluminum will bind more strongly to other substances that get introduced over time and then get filtered out, leaving the CYA behind.

Note that the phosphate removal aspect of this is incidental. It's really the iron removal that is most relevant as that is the problematic element entering into your pool causing staining.

 

[smallpooldad]

chem geek,

Thank you for the kind reply. It seems from your reply that you agree this method using Aluminum Chloride and an Acrylic Acid Copolymer does remove iron, both ferrous (Fe2+), and ferric Fe3+. (aka rust).

Here is a very rough outline of what the process might look like. Please feel free to revise it so it may work at its optimum level. Once you have done that I will create as simple as possible detailed plan, based on 10,000 gallons, so others may use it.

It seems that at the end of Hydrogen Peroxide (HP), please note 4 times the original amount in the original HP post of some months back, with Ascorbic Acid (AA) reaction creates mainly ferric iron and other perhaps other ferric items, this per your previous remarks on the HP method some months back.

The HP and AA method primary purpose is to remove both calcium and silica scale, although it also reduces orthophosphates as a bi-reaction, and also turns ferric iron rust stains into ferrous iron . If neither type of scale is present then AA method, whose primary purpose is to turn iron rust stains into ferric iron may be used solely, this might be the case in pools that are relatively young, say 2 to 8 years old, that have been otherwise well balanced, have had the same owner, and do not have heavy ppm of silica scale in their fill water such as Oahu, Central Valley in California, and many parts of Texas, Mexico, and Puerto Rico.

Question: Or do you think it safer to go with HP as well as this turns it into ferric, and might be more easily removed by the Aluminum Chloride flocculation, in party with the Acrylic Acid Copolymer? And is an HEDP sequestrant such as Jack's Magic Purple Stuff really needed to optimize the overall performance?

Then it might be best, after vacuuming and then backwashing, while the pH is low (at about 6.7/6.8), to then immediately add Aluminum Chloride (such as Natural Chemistry's Phos-Free Commercial - NOT REGULAR) and then an Acrylic Acid Copolymer (such as Jack's Magic Magenta Stuff) through the skimmer; 2 or 3 hours before dawn. This would save money on Muriatic Acid, and would not require lowering the pH again. Then just prior to dawn add back sufficient chlorine to raise it to maintenance levels for the appropriate Cyanuric Acid (CyA) level, adjusting the pH to 7.0 for 48 hours, with Muriatic Acid.

Then vacuuming and then backwashing, and allowing the pH to rise to 7.5 to remove any ferrous iron, adding more Aluminum Chloride (such as Natural Chemistry's Phos-Free Commercial - NOT REGULAR) and then an Acrylic Acid Copolymer (such as Jack's Magic Magenta Stuff), rebalancing the alkalinity. Then backwashing one more time 48 hours later. Then finally adding one cup of Aluminum Chloride to the skimmer where it should be replenished weekly, a weekly 5 oz dose of an Acrylic Acid Copolymer, and a initial full startup dose of HEDP (Jack's Magic Purple or Pink Stuff) further adding a weekly dose as measured by a sequestrant test kit thereafter.

The reason I feel staring the Aluminum Chloride at a pH of 6.7/6.8 might be a good way to go is that, according to the paper below, ferric iron is more easily removed at a lower pH, optimally 4.0 to 5.0, which would very dangerous to a swimming pool.

http://www.polytechnic.edu.na/acade...ts/Activated_Sludge_ChemicalPrecipitation.pdf

Ferrous Iron, according to that paper, is more easily removed at a pH of 7.8, or above, so a pH of 7.5 seems a reasonable compromise.

As regards your reply concerning CyA, that makes lot of sense.

Thank you, for your kind help and look forward to your reply.

 

[chem geek]

If you have chlorine in your pool then you won't have any free ferrous ions. The only ferrous would be that which is bound by metal sequestrants such as HEDP. All the rust stains would be ferric iron with oxides-hydroxides and any free iron in the water would be ferric though not much since it isn't very soluble so most will stain or precipitate.

The aluminum tends to coagulate/flocculate better at lower pH and the DIN 19643 standard specifies a pH between 6.5 and 7.2 for aluminum salts and between 6.5 and 7.5 for iron salts (remember they can use ferric iron salts for coagulation as well). The idea for coagulation is having a highly charged (+3) ion that tends to attract and disrupt charge repulsion of negative particles including cell surfaces.

Note that what you remove with PAC and copolymers is not iron ions so much as iron oxides-hydroxides. What I don't know is whether you will get as much thorough iron removal from only using the PAC and copolymers. You may need the other methods you used that involved hydrogen peroxide and phosphates. You should let us know if just using the PAC and copolymers continues to keep your pool from getting iron staining even when there is no more addition of phosphates from HEDP. The silica you get may also be a factor in which case this would not make this approach general for those getting iron introduction without silica, say from well water.

 

[smallpooldad]

Chemgeek,

An update, and success:

It has been over 3 months now!

Using the PHOSfree Commercial Strength, manufactured by "Natural Chemistry", coomonly known as a PAC (PolyAluminum Chloride), and the Jack's Magenta Stuff (Acrylic Acid Copolymer), continues to keep the pool from getting any iron staining whatsover, despite no recent addition from HEDP (Jack's Purple Stuff), and therefore no orthophosphates. Actually I added no more PAC since the last and 3rd initial treatment.

I have now let the pH rise to 7.7, from 7.5, with absolutely no iron issues. This is even better than I anticipated, before, if I went above 7.4, bang the iron stains would return in force. The only Muriatic Acid I now add is to offset the addition of liquid chlorine, 1.8 - 2 oz of acid, per approx. 15 oz of 8% chlorine (1 ppm in a 10,000 gal pool). Alkalinity seems to be holding at 70 -80 ppm, seems like 75. Temperatures are low 71-74 F, CyA at 30 ppm, and chlorine is kept about 6 -7 pp. High chlorine I know, the dreaded cold water winter algae is harder to control than the summer algae as the pool is in the shade 3/4 of the day. Chlorine usage is about 1 ppm per day. Orthophosphates are undetectable, so under 100 ppb. Pool will be warmed using a heat pump for the holidays to 82 F.

The (TDS) Total Dissolved Solids (ppm) is about 1210 measured with TDS meter, which is just barely above the Total Chloride (ppm NaCl) at around 1010 ppm, also measured with strips. So it seems the pool is fairly clean of excess TDS, and this to might be why the success, it used to be between 1500 and 1800+. Calcium is around 360 ppm, giving a Calcite Saturation Index (CSI) of about plus 0.01.

As you know from the previous post I believe I removed not only the orthophosphates but also the silica (levels around 50 to 55 ppm) from the water using 3 treatments of PAC, since that date I have not added any additional PAC. I do add 5 oz of Jack's Magenta Stuff (Acrylic Acid Copolymer) per week, but no Purple Stuff (HEDP), although some 5 ppm to 12 ppm might be useful if one has really bad well water, or municipal water, iron issues.

The HP and AA treatment was solely to remove years of Silica/Calcium Scale buildup on the surfaces, hopefully I will not have to do this again.

Even the white skimmer basket and white temperature gauge have not the slightest sign of staining or dicoloration

Interestingly my neighbor's yard persons always wack pieces of red dirt, Hawaiian mud laden with rust, into my pool, despite my admonishments not to. This occurs once every 3 weeks, but unlike in the past where the pieces of mud left iron stains in the places it fell to, the copolymer appears not to allow this to happen. As most of our staining in Hawaii comes from this wind born dirt I it seems that the copolymer is binding the iron. It also seems to remove the yellow glue-like stains that the 2 inch long Hawaiian slug leaves in the pool when they occasionally fall in, if the slug is removed on the same day. Usually this glue once it sets is nearly impossible to remove even with heavy scrubbing with a wire brush. Also I am no longer getting any "lawn shrimp" after very heavy rains, maybe there is nothing to eat that they like in the pool, or possibly the copolymer is dissolving them.

http://entnemdept.ufl.edu/creatures/misc/amphipods.htm

As my iron is wind born and presumably not as bad as iron from some well waters or municipal systems, it might be necessary for those persons to at least initially increase the amounts of "PAC" treatments, and add additional amounts of copolymer weekly to achieve the same results. I may need to add PAC in the future, primarily I think to remove silica in the water from replenishment. As it is expensive, I am seeing if I can hold off, adding it perhaps every 3 months. And then only to treat using only one cup from the jug's top. From my experience the main controller of iron is, it appears, the copolymer.

And finally here are a couple of additional interesting web papers:

http://books.google.com/books?id=6o...c acid copolymer effect on alkalinity&f=false

http://lubrizol.hk/DispersantsWater...ntifoulant-for-Controlling-Silica-Fouling.pdf

Anyhow I am a very happy camper, no more iron worries. But please bear in mind this is not a saltwater pool anymore, so your experiences might be different if you have an SWG.

Hope this helps.

Post Script:

If testing phosphates (Orthophosphates) a good inexpensive test kit available from most pet stores is the API (Aquarium Pharmaceuticals) Phosphate PO4 3- kit (150 tests for about $10 - $12). But if your chlorine is 5 ppm or above your will need to add 1 part tap (or better still distilled) water to one part pool water otherwise the high chlorine levels will bleach out ( lower the real reading). Then multiply your results by 2.

Testing for silica in the water supply. First ask your local water board if they know the number, or a local company that has to use very pure water in its processes. 0 to 15 ppm is not a real problem for silica scaling the first 6 to 8 years after the pool is built, then only slowly. But if you are in the above 35 ppm, and especially above 50 ppm, scaling might commence in the 2nd to 3rd year, in some parts of Texas it can reach 100 ppm.

A not inexpensive test kit for silica from Taylor Technologies, kit K-1273 currently costs $112.50. It measures 5 ppm to 50 ppm, and with dilution 50 ppm to 500 ppm. Remember you are only going to test once a year at the most.

A test kit for copolymer I cannot find but Taylor does sell a PAA (polyacrylic acid) test kit but I do not think that will work.

TDS meters are relatively inexpensive and useful and do not require a lot of maintenance, many hydroponic stores carry them.

pH meters are more expensive and require a lot of relatively expensive maintenance to keep in good shape, and thereby accurate. Unless you are good at maintenance and have other uses for them, not really necessary.

 

[chem geek]

Thanks for the results. This article that you had linked to in an earlier post describes how at higher pH silicic acid dissociates into silicate anion that can precipitate with calcium, magnesium, iron, manganese or aluminum to form insoluble silicates and these can scale. The polymeric aluminum (polyaluminum chloride, PAC) is a positively charged polymer and apparently removing both the silicates and maybe some of the iron (if already precipitated). The polyacrylic acid copolymer is a negatively charged polymer so may bind with the iron somewhat, but apparently the combination is helping you out the most.

What is interesting is that these two polymers aren't combining to form a precipitated mess. Usually when you mix a positively charged polymer with a negatively charged one, they combine and precipitate. The acrylic acid copolymer is not fully described -- it might be an ethylene acrylic acid copolymer or some other kind and there might not be enough carboxyl groups to give it enough of a negative charge to be a problem reacting with PAA.

What we'd have to figure out is whether the combo helps to physically remove iron in pools since iron in well water is the most common source of metal ion staining. Silica scale may be common where you are with your volcanic rock blown in, but if you look at reports on this forum most scale is calcium from hard water.

 

[smallpooldad]

Chemgeek,

Firstly an observation and update.

It appears the polymer, Jack's Magenta Stuff (Acrylic Acid Copolymer), is lifting calcium from the pool surfaces. The reason I state this that since my post on December 6th where Calcium was around 350-360 ppm it has now risen to 400 ppm. Prior to this the Calcium rose from around 340 ppm to 420 ppm, over the prior 3 months before December 6th. The reason it dropped a few days before December 6th was that we had very heavy rains up here in the mountains. I then drained to waste a few times to avoid water spilling over the sides, apparently around 16% or so, as the Calcium measured around 350 ppm after the draining.

What exactly is going on I am not sure. It could be that Calcium scaling is being removed, although the CSI is around +02, the temperature might have some effect at 73 F. strangely TDS is not changing and hanging in there at around 1,230 ppm. Do you have any thoughts on what might be going on?

The pool still looks very good, no iron that I can see.

As stated before I have no PAC in the pool at present. The control chemical I am solely relying on at present is Jack's Magenta Stuff (Acrylic Acid Copolymer). Although a number of water treatment facility papers stated that PAC's effects can be significantly enhanced by the addition of an Acrylic Acid Copolymer. I was using the PAC initially to remove both iron a silica from the water, Phosphate removal was a natural byproduct of this treatment

I think these procedures might work for municipal or well water with high iron content but perhaps, as stated before, at higher dosages. As regards Calcium staining, HP (Hydrogen Peroxide) it appears in somewhat higher dosages, with the addition of AA (Ascorbic Acid), not Citric Acid, seems to me from observation to remove Calcium scale, this to is stated in some papers on water treatment facility. At significantly higher dosages it does remove silica scale, again from observation.

Well I thought I might update you on this rather odd Calcium hardness build-up observation.

Have a pleasant holiday season.

 

[smallpooldad]

Chemgeek,

Update:

As of today the increasing ppm of Calcium has finally stopped occurring. It seems to have settled at 400 ppm.

Acrylic Acid Copolymer, seems from various papers to inhibit Silica scale formation, and remove Calcium scaling. Whatever little Calcium scaling was still present appears to have been removed.

Have a Merry Xmas.

 

[chem geek]

Merry Xmas to you as well and thank you for keeping us updated.

 

[smallpooldad]

Chemgeek,

An update:

As of today it has been nearly 5 months since I first tried this treatment. The pool is now still completely free of any iron staining. Even dropping Vitamin C tablets onto the steps, and bottom of the pool, show no noticeable difference or improvement.

Using Jack's Magenta Stuff (Acrylic Acid Copolymer) at a rate of 5 oz per week for 10,000 gals , on average. Since my last post in December I did once add 4 oz of PHOSfree Commercial Strength, manufactured by "Natural Chemistry", commonly known as a PAC (PolyAluminum Chloride), backwashing after a week to eliminate any silica (55 ppm in Honolulu's Municipal Water) which may have been introduced by fill water. I think I will do this 4 oz PAC treatment once every 3 months. I do this as an insurance policy against silica build up.

So it seems from this experiment's results that this method does eliminate iron.

I think that in areas with very iron rich fill water more of Jack's Magenta Stuff (Acrylic Acid Copolymer) might be required, possibly 2 or 3 times as much per week. Only experimentation will tell. But getting rid of the underlying scale first I think is very important, so that the iron has nothing to bind to. PAC treatments in these areas may need to be done monthly and not every three months.

One other observation is that the chlorine level does need to be kept on the high side, starting the day at 8 and ending at 7. This seems to keep all algae at bay, even the yellow mustard which we seem to get every winter is not returning at these levels. I think that Magenta Stuff needs slightly higher chlorine levels from observation, why I do not know. I might be able to lower it a little in the summer.

Current Measurements are : pH 7.7, Cl 7-8, Alk 70-80, CH 325, CyA 35 now (in the winter 30 - 50 in summer), about NaCl 1010, TDS about 1200, Temp 70 F.

Chlorine Usage: 1 ppm per day, about 2 oz of Muriatic Acid added daily to offset pH rise from chlorine.

The great thing about this method versus adding "The Purple Stuff" is that I do not need to keep adding acid to lower the pH to 7.4, nor add baking soda to raise the alkalinity to compensate. I only ever need to add baking soda if we get one of our torrential rain sea storms, and 60 - 70 mph winds. Otherwise pH and alkalinity stay very constant.

Two final observations, we had some fairly spectacular wind storms a few weeks ago which deposited a large amount of red dirt (iron oxide) in the pool, yet it did not stain. This was not the case before I started using Jack's Magenta Stuff (Acrylic Acid Copolymer). It would, prior to using this chemical, cause the pool to stain which could only be removed by the conventional AA method at a later date. In addition this last weekend my wonderful next door neighbor's yard service knocked a fair amount of mud in large lumps via weed whacking (aka Red Dirt - Iron Oxide) into the pool. When I returned in the evening I did remove the lumps but there were large stains that despite brushing I could not remove, however 2 days later they had disappeared. So it seems this chemical is good a lifting stains.

Hope this helps.

 

[chem geek]

Thanks again for the update. It sounds like you've got a good coagulation system in your pool to remove both silica and iron from your pool on a continual basis. Do you notice this removal (especially the iron that should be reddish in color) in the filter when you backwash?

It is definitely interesting how the acrylic acid copolymer is not just coagulating iron oxide out of the pool but removing stains as well. As I noted, the polyacrylic acid copolymer is negatively charged so could bind to iron. This paper talks about how poly acrylic acid copolymer (and other related polymers) stabilize iron and other metals to prevent metal staining. They don't talk about stain removal, but stabilization (binding) is likely the mechanism for such stain removal.

 

[smallpooldad]

Chemgeek,

Thank you for the quick reply and link to the paper.

It was interesting to note in that paper link that they to came to the conclusion that the amount of copolymer to be used will vary with the iron, and other contaminant loads in the water. So 4 oz or 5 oz a week is really only a starting point.

As regards stain removal the following might be of interest.

When the pool was finished, about 18 years ago, there appeared to be in one small section a small dollar coin sized dark purple smudge. The contractor was willing to fix it by removing that piece and plastering over it. I decided against it as it was quite faint and thought it might compromise the integrity of the surrounding plaster.

About 6 years later with quite of bit of scale and iron staining I was talked into an acid wash. Was that ever a mistake, it did not help in the least with the majority of stains but did, in my opinion compromise the plaster with light pitting. It also revealed this smudge to be a dark purple dollar sized spot. Over the years with further scaling re-occurring it faded into the background. Possibly created by a small piece of manganese being present perhaps as soil in the original pour.

After the Hydrogen Peroxide treatments with Ascorbic Acid were finally finished it re-appeared as this dollar size dark purple spot. But with the weekly addition of the chemical Jack's Magenta Stuff (Acrylic Acid Copolymer) it is slowly but surely being removed. Presently there are 4 small match stick size spots left after 5 months or so of treatment, these spots grow slightly smaller as time moves forward. So I do think that apart from binding iron, manganese, and scale it will lift stains.

In answer to your question, I did not notice any reddish color in the filter backwash, the color tends to off white veering to yellow. As I wrote previously after doing the final Hydrogen Peroxide treatments with Ascorbic Acid, "there was literally a little beach of sand both light colored and orange colored sand/crystals at the bottom of the pool after draining", the color on backwash now veers to the lighter yellow side. A word of caution, I have a very rare form of color blindness in the area of red/yellow/orange. It is relatively mild but I cannot guarantee it is not red.

One final observation.

You wrote in post above that PAC and the Copolymer might bind and create a sludge. I noticed that when I added the 4 oz of PAC that the pressure in the filter did rise a little, even with this very small amount, so you could be correct. It might be best after one does the Hydrogen Peroxide treatments with Ascorbic Acid to NOT add the Copolymer, first but to first treat with PAC (Aluminum Chloride) say 52 oz (minimum - heavily iron laden water might require more treatments of 52 oz) in a 10,000 gallon , then backwash after a week or so, and then add the initial 32 oz of the chemical Jack's Magenta Stuff (Acrylic Acid Copolymer), continuing with 5 ounces weekly, or more if the water has a lot of iron when topping off.

Unless you think that adding both together might be more beneficial, so long as they do interfere with each others performance.

I asked Taylor Technologies as to whether their Polymer Test can be used for Copolymer, this was their reply. I am not sure I can fully understand it, and what question I should be asking Jack's Magic:

"Response from R&D:

Yes, will give the amount of acrylic acid polymer portion of the co-polymer. The test was standardized with ploy acrylic acid salt Acumer 1000 from Rohm & Haas. It is a low molecular weight sodium salt of acrylic acid. If the polymer has other polymers such as styrene or maleic acid portion linked they will not precipitate during the test time: only the acrylic acid polymer does. Find out from your customer how many and which polymers are linked in this Acrylic ”COPOLYMER”."


Hope this helps.

 

[chem geek]

Basically Taylor is just saying that their test will measure the amount of acrylic acid polymer. Other polymers won't get measured. For your purposes, that should be OK since they go together so measuring one component is good enough to give you a rough idea of how much is in the water.

 

[hdjii]

I have been following this thread and the others related to the removal of stains on pool surfaces as I am working on this problem in my 10K gallon pool.

When I purchased my home two years ago, I found the 14 year old pool had dark brown stains on the sides of the pool with lighter stains on the bottom. I surmised that a pool cleaner of some kind had kept the bottom cleaner than the sides as there was a scalloped edge between the darker and lighter stains suggesting a repetitive rotating mechanical brush had been used over a long time period. As I studied the excellent information in this forum and learned more about pool chemistry, I concluded that the previous pool owners had not maintained the pool very well. It has a fountain which aerates the water and raises the pH such that a cup or so of acid is required each week that it is used. The water here has some iron, so I believe that the pH was probably high much of the time and that scale formed over time eventually becoming the thick deposit that I am dealing with.

Since the stain looked like iron deposits, I tested with ascorbic acid in a sock and sure enough, the color did get lighter. I treated the entire pool as described in this forum and the pool got much lighter. However, the stain was still present and very apparent due to the scalloped edge which remained.

After a lot of additional research, I continued this project by doing an acid treatment in situ also following the reports in this forum. I used about eight gallons of muriatic acid for about a week. Since I could not bypass my heater, I did not use the pump to circulate the water during this treatment but stirred it frequently myself. This resulted in significant additional lighten of the stain. In addition, a significant amount of coarse brown and clear "sand" was generated. I did not measure the amount, but it was several cups. As this point, I concluded that the major problem I had was scale and that the iron was co-deposited with the scale. The scale probably consists of calcium carbonate and iron oxides, but could also include silicates and phosphates.

I could do another acid treatment, but if the approach described in this thread would work, I would prefer it. After reading all the relevant information in the forum, I am a little unsure of the exact chemicals and concentrations to use, and what sequence to use them. I think that if I can lift the remaining scale, I will finally have the clean pool surface I have been trying to achieve. Perhaps small pool dad would give me some suggestions based on his experience? I would appreciate some help.

 

[smallpooldad]

hdjii,

Would be happy to help, with a brief as possible explanation of the treatment/method. Which might still be a little lengthy.

It might take a few days before I can post it.

In the meanwhile a few questions:

1. What chlorination method do you use, what is the size of your pump, and what filtration method do you use, what is the size of the filter?
2. Can you ask your local municipal water company what silica content of the water is? If they do not know an industrial company might; such as a paper mill, manufacturing of wood for housing, or perhaps a sewage treatment plant, or possibly your local EPA government office. If this information cannot be found, if you are willing, what city, town, area and state do you reside in?
3. Can you do a phosphate test? The least costly are the ones available from pet stores, about 150 aquarium tests for $10 . A caution here, do not remove any phosphates at present, they actually help in the removal of iron and scale.
4. What test kit are you using, and what are the current results including temperature?
5. Do you have a hydroponic store near you, and do they stock Hydrogen Peroxide, if so what are the container sizes, the strengths - typically 25% or 29%, and the costs? If the answer is no such stores, do you have a Walmart close to you?
6. Do you have any idea on the age of the pool, and I presume it is plaster?
7. What chemicals other than, chlorine, acid, CyA, and baking soda, do you put in the pool? If there are other chemicals how much do you use in fluid or weight ounces, and how often?
8. Can you get access to an inexpensive TDS (Total Dissolved Solids Meter) from a friend who grows hydroponic items, or are you able to purchase one? They help in knowing whether or not you have reduced most of your scale in the water itself. An inexpensive one, such as the "HM Digital TDS-4 Pocket Size" costs around $20 -25. If you buy from a hydroponic store, they should calibrate it for you for free. Cautionary note here: Don not let the water rise above the indicated level or you might break it.
9. If you can borrow, but do not to buy, an electronic pH meter from a friend who grows hydroponic items, it does make life easier in the initial stages. Again there is no need to buy one.
10. If you have Microsoft Excel download Chemgeek's excellent spreadsheet, Google "poolequations.xls spreadsheet, if you do not already have it. It makes life so much easier in the long-term.
11. What type and make of heater do you use? Does it have a titanium, or copper coil? How much would a plumber charge you to get a bypass put in?
12. When you did the Ascorbic Acid treatment, did you drain the pool completely? I do not think so, but am just checking.

Looking forward to your reply.

 

[hdjii]

smallpooldad: Thanks for your prompt reply. I have provided answers below each question:

1. Chlorine is added daily as needed using liquid chlorine (aqueous HOCl, nominally 10.5%). Pump is 1 HP 3450 rpm. Filter is 75sq. ft. cartridge. The water normally stays crystal clear. The best indicator is the light beam which I see from the pool light at night. Any cloudiness shows clearly.

2. I don't know the silica level of the water and the county does not test for it. I do think that silica could be a problem here in Florida. I am in Manatee County west of Bradenton about 10 miles east of the Gulf of Mexico and 50 miles south of Tampa. The soil is very sandy. Also, in my case, the pool has been poorly maintained over its 14 year lifetime. Evaporation in the winter is offset at least to some degree by the dilution of heavy summer rains but the pool surface had heavy brown scale when I started maintaining it. The scale could be carbonate, phosphate, silicate, sulfate or a mixture. It clearly includes iron salts because it is brown which is lightened by ascorbic acid.

3. I do not have a phosphate test kit, but I can get one if needed.

4. I am using the Taylor FAS-DPD test kit (K-2006) and also double checking (all except TDS which is not in the Taylor kit) by using the local pool store. They match well. Currently Free Cl is 7.0, Combined Cl is zero, pH is 7.2, Total Alkalinity is 50, Ca Hardness is 275, Stabilizer is 50 and Total Dissolved Solids (pool store only) is 3000. Temperature is 68 degrees F.

5. I can get 7% hydrogen peroxide at the local hardware store for $7 per gallon.

6. The pool is 14 years old. I am not sure what the surface is. It looks and feels like a well troweled concrete surface and has small blue flecks throughout.

7. The only chemicals I have used other that those you identified are Jack's Magic Purple (32 oz) and Polyquat 60 (32 oz) which which I have used twice as part of treatment with ascorbic acid (1.5 lb) to remove iron stains from the pool surface. These treatments produce significant lightening of the brown/tan color and lots of white milky pool water. The precipitate was filtered out over two or three days leaving crystal water. Tan surface stains remained. I have added another quart of Jack's in the last two months as maintenance in the belief that this would keep the dissolved iron in solution.

8. I can get a TDS meter online if it is needed. I have reasonable confidence in the TDS readings provided by my local pool store base on the correspondence with the Taylor tests over the last 12 months. Of course, if TDS readings are needed several times a day, the pool store would not work.

9. I do not have access to a pH meter.

10. I have been using the Pool Calculator, but I have downloaded the poolequations.xls spreadsheet and have Excel to use it.

11. I have a Haywood HP 11002 heat pump with a titanium condenser. I could get the connectors to do a bypass for about $50.

12. I have not drained the pool. Note that I have done two ascorbic acid treatments. After the first ascorbic acid treatment, I did an "acid bath" as described by TXFlyGuy, http://www.troublefreepool.com/threads/37821-2nd-times-a-charm-No-Drain-Acid-Wash. I turned off the pump to protect the pool pump and heater and I used 9 gallons of muriatic acid for 7 days stirring manually. In addition to a lot of cloudy water, I got cups of coarse grey and clear "sand". This reduced the scale a lot but I still have tan deposits, principally on the sides of the pool. Now I can see what I believe to be the original blue pool surface showing through the scale. I estimate the scale coverage at about 60% on the sides and much less on the bottom. The tan color was lighter than ever, but still clearly visible. After rebalancing the pool chemistry, the water was crystal clear and the chemistry was stable. I maintain the Cl at 5 - 7 ppm, the pH at 7.2, the stabilizer at 50 ppm and the alkalinity at 50 ppm. I recently did a second ascorbic acid treatment, hoping to eliminate the remaining stains, but no significant change was seen.

I have now done a lot of additional research with your results being of most significance to me. I think that my problem must be dominated by the scale which had accumulated over the years in the poorly maintained pool. The pool has a waterfall which causes the pH to rise inexorable. If not monitored closely, the pH goes over 8 in two or three weeks. With iron present and high calcium (400 ppm), carbonates for sure and probably phosphates and sulfates (previous pool keeper used sulfuric acid instead of muriatic), the high pH would lead to scale. Over the years, it got very thick. I believe that the difficulty in removing the iron oxides is a result of it being co-deposited with the other components of the scale. Only the fraction of the iron on the surface of the scale is accessible to the ascorbic acid solution.

At this point, I could do an additional acid wash, but if the HP or HP/AA treatment works, it would be safer for the pool surface and less trouble overall. I appreciate your input on this project.

Howard

 

[smallpooldad]

hdjii,

Thank you for your very complete reply.

It appears from the linked two papers below, from the US Geological Survey, that you are possibly correct that Manatee County water may contain relatively high levels of both Silica, at around 40 to 60 ppm, and iron, but this varies well to well from zero to as high as 1350 ppm, probably around 200 - 240 ppm, but that is high indeed. Magnesium could also be high, as can TDS from some wells. As the two reports are quite old the actual numbers maybe higher, possibly quite a bit higher as the contents of the aquifers become more concentrated.

A quick way to tell if you have high iron, silica, or other TDS, is to look at toilets that have been in place for some years, although build-up might be milder as they are flushed. You might be lucky and have good wells.

If there is a local Hydroponic Society, Commercial Nursery, or Agricultural Extension, in your area they might know the above numbers.

If possible have the pool shop test not just the TDS in your pool but also your tap water. This will help determine both needed treatment and ongoing treatment.

http://pubs.usgs.gov/wri/1981/0074/report.pdf

http://books.google.com/books?id=8eQqAQAAIAAJ&pg=PA136&lpg=PA136&dq=silica+in+manatee+county+water&source=bl&ots=1nqfKDWDH7&sig=R7sVJQyFiOVF_tMRHQfMgBPnpic&hl=en&sa=X&ei=rx8JU5zOGYXBoATGnYCwAw&ved=0CCcQ6AEwAQ#v=onepage&q=silica%20in%20manatee%20county%20water&f=false

It would be a good idea to do a Phosphate test, or tests, however as your Chlorine level is above 5 you will need to add 1 part tap water to 1 part pool water, otherwise it will bleach out. Then double the result for a true reading. The reason for doing the phosphate test is to see if you have way more than 3.500 ppb as this would use up quite a bit of the Hydrogen Peroxide before it gets to work on the Silica, and Iron. If the level is indicated at 3,500 in the test, add an additional amount of tap water, by which I mean an equal amount to the amount your are testing, to see if it is 7,500 ppb or beyond, doubling again if it registers 7,500, and doubling again until you reach a coloration in the test which is below maximum.

Buying a TDS meter is not absolutely necessary but I find it useful as I am not as sure of the results from our pool store as you are.

3% Hydrogen Peroxide at Walmart is normally around 95 cents for 32 ounces, a gallon therefore is around $4, or $8 for a 6% equivalent. Just make sure your 7% one is not old or poorly stored. Also Walmart's is very fresh, as they have a high turnover. The reason I questioned if you can get it from a Hydroponic store, or possibly a Garden Nursery Store, is that you will not have to open so many bottles if it 25%, or 29% proof. Typically the cost is comparable to Walmart, maybe slightly more. If you do get the higher proof one just make sure it was stored away from strong lights, heat, and that the jugs are not dusty/old, as they loose potency over time. This especially true for high proof HP.

I think based on your comments about the coloration of the stains at present, and the fact the pool is 14 years old, you may need quite a bit of HP, so try to hunt down the higher proof stuff. An additional source which may prove to be very inexpensive is a chemical supply house, or a commercial nursery may sell you some of theirs, as they typically buy it in 50 gallon drums.

You are still going to need Ascorbic Acid, about 3 lbs, for 2 treatments of 1 1/2 lbs each. Also 2 bottles of the Magenta Stuff.

The fact that you have a Titanium Condenser is good news as this means you will not have to bypass the heater as they are typically unaffected by pHs in the 6.6 - 6.8 range, unlike copper.

As the water table is normally very high in Florida, I think it would be a very bad idea to drain the pool. It might pop out of the ground, if there are not enough relief holes drilled, or if the are plugged.

It sounds like the pool was well built, so yet another plus.

If you like you can let the CyA stabilizer drop to 30 ppm, as it makes it easier but not essential to do the treatments. It does make it slightly less expensive.

Three questions:

What is the pH of your tap water?

Is there a reason the Alkalinity is set at 50 ppm, versus this sites recommended 70 - 90 ppm? Typically higher alkalinity helps the jumping pH, then again you may have found the opposite to be true. Additionally if the Alkalinity is too low in acidic pool it to can cause staining. Your CSI, using the PoolEquations spreadsheet is a minus - 0.90, this is fairly acidic.

What is the Alkalinity of your tap water?

 

[JasonLion]

hdjii, by far the best way to remove scaling is a drain and manual acid wash.

 

[smallpooldad]

JasonLion,

I think it is a matter of agreeing to disagree. My personal experience with both methods is different, a prior acid wash did not remove the scale some years back, but treatments with HP and AA did. The acid wash did mark up the walls however despite being done correctly, so personally I would never go that route again. I would assume it depends on the plaster mix, but I am no concrete engineer.

Of course the HP and AA method may not work for hdjii, but hdjii is willing to give it a try, presumably as this method is less aggressive. If hdjii does give it a try we all might be able to determine whether or not it might work for others, based on the final result.

The attached link describes why certain types of scale that I had, and hdjii might have are very difficult to remove with a muriatic acid wash. Although extremely dangerous hydrofluoric acid can possibly do the job as stated in this link "Only harsh hydrofluoric acid (dangerous to handle) or mechanical cleaning methods will remove this hard scale quickly."

http://www.mcgrayel.com/files/cleaning_tips.pdf

If Chemgeek you disagree with link, please let us know.

The Wikipedia entry regarding hydrofluoric acid, illustrating clearly why it should never be used for a pool de-scaling.

Off topic third party quote removed. JasonLion

 

[JasonLion]

The acid wash did mark up the walls however despite being done correctly, so personally I would never go that route again.

If it marked up the walls, then it was by definition not done correctly.

A manual acid wash will not work 100% of the time, but it will work 98+% of the time, while no other know approach works even 50% of the time.