Best choice in test kits

[Chas]

I replaced the liner in my 27’ AG pool with 5’6” center depth this past Memorial Day and filled it with one garden hose through my home’s iron filter. Filled it at half throttle, 600 gallons between regenerations. It took two weeks to fill the 20,000 gallons in this pool. Added 144 oz. of Sequa-Sol sequestrant as it filled. Added no chlorine as it filled but added a couple of quarts of non-copper algaecide and began adjusting pH at 7.8 (½ gal. muriatic at a time) with a TA of 410ppm. Since then I’ve watched the pH closely and adjusted it when it reached 7.8. The TA is now 360ppm as of 6/15/15.

I started the system last Sunday 6/7/15, shocked the water and it went brown. During the week it cleared, I’ve been cleaning and swapping the 100 sq. ft. filter cartridges regularly upon a 10psi pressure rise and shocked it twice more in an effort to precipitate all of the iron out. Friday evening 6/12/15 I vacuumed it again, the water was clear and the pool clean. I began to run the erosion feeder at 0ppm FC with 3” tri-chlor pucks, the FC has been running around 5ppm since I started the feeder. No CYA in the pool yet other than residual from the tri-chlor pucks. Today, the water is clear but has a dark look to it. Iron or other mineral(s) is still precipitating and collecting on the walls. I vacuumed it again yesterday afternoon. Maybe I just need to be patient and let the filter work.

I plan to buy a test kit from you folks that I will use for my pool and customers’ pools. I service vinyl IG pools. In order to give me advice, what info do you need about my water? I’ve been using basic 5-bottle kits for years, those kits test for free and combined CL, pH, acid demand and TA. After reading posts and info in this forum I’m ashamed to admit that my CYA test kit has been sitting unused for the past 15 years and I doubt the accuracy in a 15 year old reagent. I gotta get with the program!

I'm leaning toward your TFP kit. What test kit would you recommend if you feel it's worth looking into minerals other than iron?

Thanks!

 

[tim5055]

I would go with the TF100 and at least include a couple of the the XL options to give you plenty of chlorine tests. That will give you what you need while you are clearing the pool, and probably enough reagents for a couple of years normal use.

The only other real option for a test kit is a Taylor K-2006. Be careful comparing prices because the K-2006 comes in sizes, designated by a letter. The basic K-2006 has .75oz bottles. Yo need to get the K-2006-C to get the larger bottles that you want. Even then it is a little short on the reagent & powder for the FAS/DPD test.

I also have the SpeedStir and Sample Sizer. They speed testing and accuracy.

 

[chem geek]

See Test Kits Compared for a comparison of the TF-100 vs. the two sized K-2006 kits. The comparison table is missing a few other differences. The K-2006 has acid and base demand tests. Usually you can just calculate what is needed using PoolMath though it isn't exactly correct for pH adjustment if you CYA is outside of normal ranges (my Pool Equations spreadsheet will calculate it exactly, but it's not for novice users). Also, the pH test in the TF-100 uses a Taylor K-1000 kit (that also has an OTO chlorine test) so has a smaller sized comparator with 6.8, 7.2, 7.5, 7.8 and 8.2 while the Taylor K-2006 has a larger sized comparator with 7.0, 7.2, 7.4, 7.6, 7.8, 8.0.

As for dealing with iron, you have several options:

• Use ascorbic acid to remove iron stains or citric acid to remove copper stains and then use an HEDP metal sequestrant added weekly to keep the metal in solution. See the Pool School article Metals in the Water and Metal Stains.
• Use Metal Magic to both remove and sequester the metal, again added regularly, though some filtration of metal may be possible. See Question about AA treatment and Metal Magic.
• After stain removal, do water replacement to remove metal if you have fill water free of metal (i.e. using trucked-in water when you have well water high in metals).
• After removing metal stains, use CuLator to physically remove metal from the water. If any problems occur with this product, contact the company as sometimes special procedures are needed when using their product.
• After removing metal stains, try and precipitate the metal onto the filter and remove it by backwashing/cleaning. See Iron Removal and Copper Removal at The PoolForum for advanced procedures using pH Up (sodium carbonate) through the skimmer to try and co-precipitate metal oxides-hydroxides with calcium carbonate onto the filter.

Metal ion test kits are rather expensive so it's the one situation where we say to use pool stores, but the Taylor K-1264 has both iron and copper tests. Another somewhat less expensive alternative is to get the Taylor K-1730 for (free) copper and the Taylor K-1716 for iron. Vinyl pools usually have less problems with metal staining than plaster pools.

If you want to accelerate the process of lowering your TA so that you get a more stable pH you can follow the procedure in the Pool School article on how to Lower Total Alkalinity via a process of acid addition and aeration at low pH.

 

[Chas]

Hey! Thanks a million, guys! This is amazing to get such in-depth true knowledge. Were or are you guys in the pool biz?

I'll check out the options that you've given me. I sure do appreciate it!

Chem geek - I see you have Fafco solar panels. I installed a few Fafco systems back in the day. Is Fafco still in business?

 

[Chas]

From the Pool School page - "If you have metals in the water you will need to use regular doses of a sequestrant to prevent the metals from forming stains. Sequestrants bind to the metals and prevent them from depositing as stains. Sequestrants slowly break down in the pool, so you need to add more regularly to maintain the correct level."

Questions on sequestrants is what brought me to this forum to begin with.

Will the iron stay in the water forever? I figured, based on past experience with my lousy makeup water and soaking brown filter cartridges in Iron Out, that eventually the iron gets removed thru filtration. Is that not the case? I'll keep reading, but, is there a way to know when to add more sequestrant? Does the sequestrant make the iron "invisible" until the chlorine level gets high?

Thanks!

 

[chem geek]

Unless you do something to remove the iron, it will generally stay in the water a very long time. That's why you add a metal sequestrant and because the sequestrant breaks down from chlorine you need to add a maintenance dose each week. Some techniques physically remove the iron from the water, but those techniques can either be more expensive or less reliable.

Iron would only get removed from filtration if 1) the iron oxides-hydroxides didn't re-stain pool surfaces and coagulated to large enough particles to get filtered for that particular filter type (microns for filtration) or 2) a product was used that explicitly consolidated iron particles to coagulate them so that they would get more readily caught in the filter.

The sequestrant does in effect make the iron invisible. If you shock with chlorine then you can break down the sequestrant faster and it will release the iron so there's a dance between adding enough sequestrant to keep binding to the iron vs. chlorine breaking down the sequestrant. This is why I listed the other alternatives that physically remove the iron from the water even though they can be more expensive up-front.

 

[Chas]

Thanks, chem geek! What you say makes sense and is proven by what I'm experiencing.

 

[Swampwoman]

^chem geek, I've long thought about trying the cal hypo in the skimmer thing, but my iron load continues to diminish now that my makeup water is via softener.

Chas, just a few things...is your water still dark? Re startup iron, as opposed to ongoing iron mgmt, there are some things sme people do to reduce -- Some folks with AGs and brown water reduce it (to an extent) by adding fabric or skimmer socks to the skimmer...one rigged up a large pop bottle filled with pillow stuffing to filter on the fill hose. Others will put something called a "slime bag" on a return to aid in the filtering (google slime bag and you'll find it.)

There is also a product of unknown efficacy called Ferritabs that some people swear by -- if the iro is oxidized, it acts like a floc in the skimmer and binds with it to carry it out. (Googe that one too, don't have links handy right now.)

I had sequestered my iron back when I recovered my swamp 3 yrs ago, and haven't shocked/slammed since, so mine never oxidizes for me to try any of these "filtering reduction techniques" But i read about them all with interest in case I ever have to slam

Hope that gives you some extra ideas to expedite your water tint while the iron is actually in a state suited for removal
Cheers to clear!

 

[Chas]

I was happy to see a little sparkle from my water this morning! After 144 oz. of Sequa-Sol, half a dozen vac jobs, 3 shock cal/hypo shock treatments and 10 (or so) filter cartridge swaps the water has cleared up nicely since it went brown with the first shock 9 days ago. The pH this morning was 7.5, FC was 3.0, I haven’t added any CYA yet. That will be my next question to ask this forum.

I'm running this pool with all inground filtration equipmernt and piping.


It seems that the sequestrant worked to keep the iron from staining, guess I’ll really know in another week or so. It’s helpful to get the info here re; sequestrants. My history with this pool has been that once the iron is filtered out, there’s no more strange colored water. I didn’t use sequestrants properly in the past, tho, and there was staining to the other two liners. Being that this will be the last liner that I’ll ever put in this pool I’m hoping that I did the water the water treatment right this time. I didn’t want to drop a grand on trucked water, nor is there easy access for a tanker.


Thanks chem geek and Swampwoman for your input!

 

[Texas Splash]

Chas, unless I missed something in your thread, you do indeed need to get some stabilizer in there right away to protect your FC (good chlorine). You mentioned you haven't added any yet, and I don't see any recent TF-100 test numbers, but without CYA your FC doesn't stand a chance in that water and will get lost to the sun quickly.

 

[Chas]

OK, thanks for that input on the CYA! I have enough on hand to get the CYA to around 25ppm, however, I was a little concerned there when the water was so brown that I may want to let the CL diminish to 0ppm if I needed to add more sequestrant. At this point, I think I may be past that concern.

But - here's my first question re;CYA - I'm using 3" sodium tri-chlor pucks in an erosion feeder. I know there is a small amount of CYA in them. After learning about the relationship between CYA and FC here at TFP, I'm thinking that's why I noticed an uptick in my problems with algae these past few years - I wasn't holding my CL high enough to actually be free CL to prevent algae growth. So I compensated with algaecide, more than I care to admit....

I'm thinking that (just because) I'd like to measure the CYA in the pool with a fresh fill and after running on 3" tabs for a couple of weeks before I actually add CYA. I need to order a test kit from TFP this afternoon. I'm real curious to see just how quickly the CYA increases by running with the tri-chlor. I run my system 24/7 and have been watching the CL to try to keep it somewhere between 3 and 6ppm for right now.

Thanks for the input!!

 

[jblizzle]

I would hardly say there is a "small amount" of stabilizer in trichlor pucks. For every 10ppm of FC they add, you get about 6ppm of CYA.

If we call your pool 19k gallons, each 8oz puck will add 2.9ppm FC (which would be a normal daily requirement) and 1.8ppm of CYA ... in 30 days you should have added about 20 pucks and thus added 36ppm of CYA.

Here is something that Richard320 wrote that explains part of the issue:

I'm glad you asked!

Here's a little something I wrote last season. I still think it's one of my best pieces of writing.

​We'll take a 16000 gallon pool, because that's what I have. On a fresh fill, prominent national pool chain recommends 2.5 pounds pf stabilizer per 10,000 gallons, which works out nicely to 4 pounds which brings CYA to 30.

With an average loss of 2 PPM/Day or 14 ppm/week, I'll have added 8.6 PPM/CYA if I used trichlor pucks perfectly. And they recommend a weekly "shock" of dichlor between 5 and 10 FC.... 2-3 oz per 10,000 gallons. Split the difference; I'll add 4 oz. CYA went up another .9.

So..by the end of week one, I have added 9.5 more CYA. It is now 39.5. Mimimum FC for that is 3, so I'm probably okay.

Week two, up to 49 CYA.
Week three, 58.5. Minimum FC should be 5, but they recommend 3 as ideal, so the pool looks a bit hazy. So I'll toss in a little extra dichlor "shock" to jack FC up to 10. Which adds another 6.4 CYA. Keeping count? We're up to 64.9 now.

That caught the algae just in time.. we had two weeks of good luck. A steady diet of pucks and 4 oz. "shock" each week only added another 19, up to 73.9 now.

Week 6 it started looking funky, so we "shocked"it once again. CYA is up to 99.3. But minimum FC to keep algae at bay is 8, and we're still holding things to 3, because prominent national chain's preprinted sheet shows that as ideal. So algae got a toehold and the pool has a bit of a tint. So we throw two whole bags of dichlor in which jacks it another 7.6 by the time week 7 is over, we're at 116.4, because we had pucks in the floater the whole time.

So...in 7 weeks, from 30 to 116.4. Let's say there are no more algae outbreaks because they sold me a huge bucket of phos-free and another of yellow-out monopersulfate "shock" Nothing but the pucks and the extra 4 oz of dichlor "shock" weekly. So the next 7 weeks added 66.5, which brings the total to 182.9 CYA.

Now if we didn't understand this and things looked a bit hazy, we might throw an extra puck or two in the floater every couple weeks, which will drive it over 200 easily.

And then next year when you try to open, you're whining here how you "shocked" it and it's still green. And then you get indignant at the cost and bother to drain 3/4 of the pool. Seen it over and over and over and over here.
​

This is all based on a roughly 3 month swim season. If you run pucks year-round, it'll be even higher.

 

[Chas]

I'm shocked! (pun intended....)

 

[Chas]

I just ordered a TF-100 test kit. Am looking forward to providing those test results with further questions. My once brown pool full of iron 9 days ago is now shimmering clear, CL at 4.0 and pH at 7.5. I'm wanting to keep it that way!

Thanks all for your input!

 

[AimeeH]

OK, thanks for that input on the CYA! I have enough on hand to get the CYA to around 25ppm, however, I was a little concerned there when the water was so brown that I may want to let the CL diminish to 0ppm if I needed to add more sequestrant. At this point, I think I may be past that concern.

But
- here's my first question re;CYA - I'm using 3" sodium tri-chlor pucks in an erosion feeder. I know there is a small amount of CYA in them. After learning about the relationship between CYA and FC here at TFP, I'm thinking that's why I noticed an uptick in my problems with algae these past few years - I wasn't holding my CL high enough to actually be free CL to prevent algae growth. So I compensated with algaecide, more than I care to admit....

I'm thinking that (just because) I'd like to measure the CYA in the pool with a fresh fill and after running on 3" tabs for a couple of weeks before I actually add CYA. I need to order a test kit from TFP this afternoon. I'm real curious to see just how quickly the CYA increases by running with the tri-chlor. I run my system 24/7 and have been watching the CL to try to keep it somewhere between 3 and 6ppm for right now.

Thanks for the input!!

Chas, have you discovered the Pool Math link at the top of the page? http://www.troublefreepool.com/calc.html

If you enter all you information, scroll to the bottom and there is a section where you can calculate the effects of adding different chemicals.......since your curious about CYA and pucks.

 

[chem geek]

But - here's my first question re;CYA - I'm using 3" sodium tri-chlor pucks in an erosion feeder. I know there is a small amount of CYA in them.

What Jason wrote from Richard explains it well over a season, but I want to emphasize that your statement is wrong about a "small amount of CYA". The following are chemical facts that are independent of concentration of product or of pool size:

For every 10 ppm Free Chlorine (FC) added by Trichlor, it also increases Cyanuric Acid (CYA) by 6 ppm
For every 10 ppm FC added by Dichlor, it also increases CYA by 9 ppm.
For every 10 ppm FC added by Cal-Hypo, it also increases Calcium Hardness (CH) by at least 7 ppm.

So with Trichlor it can most certainly build up CYA quickly. When I first got my pool and knew next to nothing about pool water chemistry, I used Trichlor pucks in a floating dispenser. Because I had a mostly opaque electric safety cover and the pool wasn't used as frequently, I had a fairly low 0.7 ppm FC per day chlorine usage -- roughly adding one 3" puck every 5 days in my 16,000 gallon pool. Though I started out at 30 ppm CYA, after a year and a half with a 7-month swim season (not much chlorine usage over the winter with the colder water), my water started to turn dull/cloudy mid-way in the second year. This was in spite of using Algymycin 2000 algaecide (a mix of Polyquat 60 and linear quat algaecides), though only every other week. The CYA had climbed to 150 ppm and I was experiencing the early stages of an algae bloom. I had stupidly not used winter rains to dilute the pool water. That's when I decided to dive deep into pool water chemistry. Note that (0.7 ppm FC/day) * (0.61 ppm CYA/ppm FC) * (11 months) * (30 days) = 141 ppm CYA which added to the initial 30 is 170 ppm less around 20 ppm lost from slow oxidation and some splash-out.

 

[Chas]

Geezez.......I'm amazed! I'm feeling like I've let many of my customers down, and myself, through the years because I sure wasn't aware of the scope of the CYA. I wonder why the chemical manufacturers put so much in their product? Not to sound lame, but .....really? Do they do that so they sell more product? Or is there another factor?

I was over at a customer's house this evening cutting in a 3 way valve so he could build a solar system for his pool. This was the most recent, and probably the last one I'll do, IG pool I built - 3 seasons ago. Big pool, custom shape, cloudy in the deep end. Um....sound familiar? We discussed water chemistry at length, and I made him write down the URL for TFP and told him to get to reading here. I may make up a card and just hand it to all of my customers.

Thanks a billion! I did order a T-100 test kit today. Can't wait to get it!

- - - Updated - - -

Thanks, AimeeH - I have looked at it but haven't spent much time there yet. I'm fascinated by theory and science right now!

 

[chem geek]

The CYA is not added separately. It's part of the molecule, basically where the CYA holds three chlorine atoms in Trichlor (compare Trichlor with Cyanuric Acid). That's why the 10 to 6 ratio of FC to CYA in Trichlor is fixed.

Unfortunately, there are a limited number of choices for chlorine chemicals:

• Sodium hypochlorite - only safely usable as a diluted solution in water and it degrades faster at higher concentration so 12.5% or 15% is about the highest concentration you will see.
• Calcium hypochlorite - it gets up to around 72% in concentration though anything above 50% is a potential fire hazard; it adds calcium to the water; it's mostly granular because pucks require gooey binders that often leave a residue.
• Trichlor - available as a somewhat slow dissolving powder, but mostly used where that powder is compressed into pucks that is even more slowly dissolving and therefore quite convenient; it adds CYA to the water. This is also the most concentrated form of chlorine other than chlorine gas so is less to carry by weight.
• Dichlor - only available as powder/granular and it dissolves very easily in water, but increases CYA even faster than Trichlor (because it only has 2 chlorine attached to CYA instead of 3).
• Lithium hypochlorite - it is typically 35% available chlorine and is a powder/granular and dissolves quickly. The main downside is that it is the most expensive form of chlorine.
• Chlorine gas - this is the most concentrated form of chlorine but it's dangerous if not handled carefully so not used very much (only used by some commercial/public pools and some "gas shooter" pool services).

 

[Chas]

This topic if CYA and chlorine is becoming more fascinating by the post! I stole a little work time this morning and was googling around on this subject. It led me to a couple of other good websites, all of which agree with what you've been saying (not that I doubted you, I was just becoming more interested). I noticed that TFP was linked to and chem geek credited by real name with writing.

While googling, I found this post (from last August?) by chem geek - "Well the chlorine/CYA relationship was definitively determined in 1974 when all the equilibrium constants for the chlorinated cyanurates were accurately determined. Even so, it's not so much that the relationship wasn't understood by some chemists, but they were working for chlorinated isocyanurate manufacturers and it was not in their economic interest to disclose this relationship. They sold Trichlor and Dichlor and not only made money doing so, but made more money selling clarifiers, flocculants, algaecides, "shock", etc. that are needed to combat the problems with higher CYA (and not proportionally higher FC) and these products have a much higher profit margin."

Man does this open my eyes to some of my shortcomings in knowledge of pool chemistry. During the '80s I worked at a resort where I ran a 100,000 gal. outdoor pool, a 50,000 gal. indoor pool and 4 - 1,000 gal. whirlpools, also late '80s for a couple of years I ran a 60,000 gal. indoor pool and 1,000 gal. whirlpool for a health club. Everything was sanitized with 12% sodium hypo through feeder pumps, I installed a ORP/pH controller for the indoor pool at the resort. The outdoor pool was the only pool where I added CYA. Never had to add algaecide to that pool, I remember attributing that to my motto of "always always always maintain at least 2ppm of free chlorine". We used the DPD #1 and 3 tests for FC and CC, shocked the outdoor pool pretty hard on some Mondays after an extremely heavy weekend swimmer load. We used to laugh about what must be in that water, there was always poolside alcohol freely available. The water-aerobic instructors would sometimes call in a "turd alert"......

In retrospect, the evolution of my "learning" may have pretty much stopped right around the late '80s when I quit those jobs and went back to building/servicing IG pools. By that time, chlorine erosion feeders had become pretty standard in my area and my new pools all included a feeder as part of the package, as did the appropriate amount of CYA for a freshly filled pool. Acid to lower the pH and TA, test daily, shock and algaecide spring and fall, pucks in the feeder and you're good to go.

I still service a couple dozen longtime customers' pools spring and fall on a part time basis yet and have noticed a trend when opening pools in spring with pH and TA being quite low; 6.5 - 6.8 and 20 - 40ppm. This became much more common as we entered the 21st century, I attributed it to "acid rain/snow". Most pools here use mesh winter covers. I've been selling Alk-Up and pH-Up products to just about every customer in the spring. Now, to connect the dots, I observed in my own pool that the tri-chlor would tend to decrease the pH and TA, I too was adding pH and Alk-Up products. And in the past few years, my customers have reported an increase in algae problems that I too noticed in my own pool. I haven't heard customer comments about cloudy water, but, I do pump maybe 20-25% of the water out of their pools when closing for winter. My own pool, though, is left to winter over with very little pump down. My customers' pools may be getting enough spring makeup water to dilute the CYA down where my pool does not.

So - thanks, chem geek and everyone else for opening my eyes on this subject. I guess my brown pool water that got me to find this forum was a blessing in disguise!

 

[tim5055]

You would think that in 40 years the industry could catch up, but with a combination of government involvement (EPA & many states regulate commercial pools) and no real push from the industry it ends up being a situation where the new pool guy learns from the old pool guy and new ideas don't get introduced. Pool "professionals" say they have been doing it for XX years and have never had a problem.

We do owe Chem Geek (Richard) a lot of credit for keeping up with the science!