Stain Wars--Planning the Next Assault!

calinb

Well-known member
Jul 18, 2018
121
N. Central, ID
I did a Metal Magic sponge test late last season and it indicated that I treat my stains with the maximum dose of MM. (Here are the highlights of that battle: Sequestrant vs. CYA Bound Chlorine ).

The MM lifted nearly all my dark gray stains and I continued to treat with a maintenance dose of MM until I closed the pool and then did a maintenance treatment again when I opened the pool early last month. In time, (about a couple of months total) my Culator Ultra 4.0 even turned yellowish-brown, swelled, and then shrank back down and got all crunchy inside. Whaddaya know, Culator skeptics (perhaps chem geek notwithstanding), but that's what Culator says will happen when the contents of an "egg" fill up and become spent!

Now I'm left with lighter tan stains that do not respond to a MM sponge test. Trichlor pucks do nothing to them. Ascorbic acid tends to darken the remaining stains (adds a gray color). but citric acid lightens them a little. The only thing that has lightened them significantly (yet not completely) is the Copper and Scale Stuff in Jack's Stain Test. The ID kit O2 and Iron Stuff combinations do not enhance the stain removal action compared to Copper and Scale Stuff alone, so I guess I'm left with mostly copper stains, which isn't surprising, given that the previous home/pool owner left a nearly empty giant blue bucket of nasty blue-speckled trichlor pucks in the pool shed. A professional lab result says our spring water contains 4.4 ppm iron and 0.0185 ppm manganese but essentially no copper, so the "plus-enhanced" trichlor pucks are almost surely the source of the remaining stain problem.

I'm thinking about treating with citric acid or perhaps sulfamic acid to see if the stains will lift (leaning towards sulfamic acid, because the Jack's Copper and Scale treatment produced the best results).

Both citric and sufamic acid treatments appear to impose post-treatment challenges. Citric acid chews up chlorine like crazy during post-treatment re-balancing and sulfamic acids seems very likely to knock alkalinity and pH off the map! I guess either method might produce another big dust cloud in the water like the one that cost me the end of the swimming season last year so maybe I'll wait for the water temp to hit 65 F before I begin my next full-on stain assault (too cold for pleasant swimming but still barely warm enough for stain treatments). It's now a very pleasant 78F. :love:

What to you experts here at TFP think? Citric or sulfamic?

Are the specialty formulations of Jack's sequestrants worth the extra money over just the plain ol' HEDP in MM?

Thanks a bunch for thoughts and advice!
 
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JoyfulNoise

TFP Expert
Platinum Supporter
May 23, 2015
18,606
Tucson, AZ
Pool Size
16000
Surface
Plaster
Chlorine
Salt Water Generator
SWG Type
Pentair Intellichlor IC-60
The MM lifted nearly all my dark gray stains and I continued to treat with a maintenance dose of MM until I closed the pool and then did a maintenance treatment again when I opened the pool early last month. In time, (about a couple of months total) my Culator Ultra 4.0 even turned yellowish-brown, swelled, and then shrank back down and got all crunchy inside. Whaddaya know, Culator skeptics (perhaps chem geek notwithstanding), but that's what Culator says will happen when the contents of an "egg" fill up and become spent!

Just because the vendor tells you what will happen and then claims that that means the product is "working" does not constitute actual evidence that it is doing anything useful ...that is a logical fallacy. The fact is, the CuLator is nothing more than a package of ion exchange resin. All ion exchange resins will become swollen and brittle when exposed to a hard water environment, especially one that is highly chlorinated like a swimming pool because the chlorine oxidizes and destroys the resin material. All ion exchange resins will absorb some metal....but the chemistry tells you that they are NOT selective. They will absorb any divalent metal that's in the water (Ca, Mg, Fe, Cu, Ni, etc, etc) and they will do so in accordance with the concentration of those ions in water. So, the CuLator sack will absorb mostly calcium because pool water has hundreds of times more calcium hardness than iron or copper. Will some iron and copper get absorbed, sure. But not enough to make a difference. Finally, the design of their product is silly - a package is left inside a plastic cage that sits in the skimmer or pump basket. 99.9% of the water in the plumbing system will flow around the bag, not through it. Therefore, the CuLator absorbs only those ions that diffuse into the bag. This is why water softener manufacturers, or any manufacturer of an ion exchange system, use exchange column designs, ie, water is forced to flow through the resin bed so that there is maximum surface area in contact with the water and a long contact time. As well, exchange resins are routinely flushed and regenerated to avoid the degradation and cracking that will occur when they become overloaded with absorbed metal ions.

Sorry, but the CuLator is, at best, a placebo.

Now, on to advice about how to deal with your copper stains. The Jack's Magic sulfamic acid regimen will more than likely remove the copper from the surface of the pool and redissolve it (and some of the plaster) back into the pool water. It will also screw up your DPD-FAS testing and show up as falsely high CCs. So you have a choice - redissolve the copper and try to manage the pool with sequestrants OR redissolve the copper and then dump some or all of the pool water. The only way to be absolutely sure that the copper stains will not return is to get the copper out of the pool. The only way to do that is to dump the pool water. A partial drain might lower the copper concentration enough so as to not be an issue but without a concentration level, it's hard to say. SO it's up to you and what you can afford to do safely. Emptying a pool can only be done safely if you are sure there is no ground water in your area that could cause the pool to float. If ground water is present near your pool, then you'll have to do some kind of exchange draining where you draw water out of the deep end while slowly filling in the shallow end to prevent turbulence and mixing.
 
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calinb

Well-known member
Jul 18, 2018
121
N. Central, ID
Sorry, but the CuLator is, at best, a placebo.
The color is allegedly an indication of the type of metal ions. I had the Culator in my pool for two months before I did the MM treatment and the Culator did not change in appearance during the entire two months. Within a couple of weeks of the MM treatment, which dissolved essentially all my dark gray stains, the Culator color became noticeably yellowish-brown and it has continued to become darker since then. It makes sense that it takes awhile, because the water "turnover" past it and within "ion capture range" is probably relatively low. Perhaps running the pool water through a Culator fastfill element would work faster but who cares if it takes a couple of months, if you can hold the ions in the water with sequestrant while you wait?

I'm not yet ready to conclude that the Culator egg definitely works as advertised, but I've read the information that chem geek has posted about the technology and I don't think chem geek claimed that the product works either, but I believe it's safe to say that he has not drawn the conclusion you draw, above, nor have I. In fact, I recall that chem geek was essentially soliciting feedback and reviews on the product, or at least that sort of interest was the implication I took away from his posts on the subject.

In summary, the appearance of my Culator egg didn't change for two months but did change significantly in the two months immediately following the MM treatment (to this date), where the MM lifted essentially all my dark gray stains and they have not returned--perhaps because of the MM maintenance additions but Culator prescribes such additions to keep the metal ions in the water while the Culator works too. Nowhere does the Culator manufactuer claim that it, alone, can remove stains. My Culator color change was also consistent with the manufacturer's diagnosis of iron stains.. Coincidence? Yes--possibly. If I can now manage to rid the pool of what I believe to be Cu stains (based on the Jack's test and ascobic and citric acid results), I would like to try using a new Culator along with continuing sequestrant maintenance. If the pool gets to the point that the Culator stays white, I'll discontinue the sequestrants. If the stains don't come back, it would be reasonable to conclude that the Culator works! How else could the metal have left the pool? Of course I'll need to find another source of fill water that is metal-free too, which might actually be viable now that I've found and plugged a 165 gallon per day leak in our pool and it now passed the bucket test with flying colors! I could probably bring enough fill water in with my pickup truck and 55 gal. drums to cover evaporation and filter backwashing.

Now, on to advice about how to deal with your copper stains. The Jack's Magic sulfamic acid regimen will more than likely remove the copper from the surface of the pool and redissolve it (and some of the plaster) back into the pool water. It will also screw up your DPD-FAS testing and show up as falsely high CCs. So you have a choice - redissolve the copper and try to manage the pool with sequestrants OR redissolve the copper and then dump some or all of the pool water. The only way to be absolutely sure that the copper stains will not return is to get the copper out of the pool. The only way to do that is to dump the pool water. A partial drain might lower the copper concentration enough so as to not be an issue but without a concentration level, it's hard to say. SO it's up to you and what you can afford to do safely. Emptying a pool can only be done safely if you are sure there is no ground water in your area that could cause the pool to float. If ground water is present near your pool, then you'll have to do some kind of exchange draining where you draw water out of the deep end while slowly filling in the shallow end to prevent turbulence and mixing.
I'm not too worried about having false high CCs in DPD-FAS tests, because I never have measureable CCs even in the swim season and I'll probably do the treatment at the very end of swim season. Jacks just recommends using TC alone as the chlorine indicator (assume that the false CC reading is actually an indication of your FC).

Our spring can't fill the pool. It would require trucking the water in over a very narrow, tight, twisty and mountainous gravel road (low weight limits). When the previous owner did it about 20 years ago after a drain and acid wash, it took 19 truckloads of water ($$$). The pool didn't float when he did it in July but his retired local (50 miles away) pool guy that did it 20 years ago advised me over the phone to only consider draining the pool in the fall, due to the risk of floating it! I honestly think we have the only swimming pool for nearly 50 miles in any direction arould these rural woods! Maybe someday I'll do a Google satellite search and see. Ha! It's funny, because all the local kids get on a "swim bus" up to twice per week in the summer to visit the "local" pool, which is about 1-1/2 hour bus ride away! I'm getting off-topic but our pool has some history around here from the day a very successful realtor owned this old homestead and had the pool built.

At this point, it makes sense for me to continue to try to lift the remaining stains and thanks for your suggestion that sulfamic acid stands the best chance of at least accomplishing that part of the process. Draining the pool just doesn't make sense yet. Culator products and even Jack's products are just too cheap to give up on continung the process I've used, compared to water tanker truck deliveries and the risk of pool float.

Given what I've observed with the Culator, I think I'll buy a Culator pleated 2.5x10 filter and pre-filter all my fill water. I might also circulate pool water through it via the pool's old cleaning tool return. If I can lift the stains and use MM (or Jack's Blue or Purple Stuff, which is supposedly formulated more for copper) and the stains don't come back, I'll look for a zero color change in the Culator. If I achieve that results, I discontinue the sequestrant and see if the stains come back.

I know you money is on "they will"!

I think that's my broad plan, but it would be great to hear more from TFPers about the merits of Jack's Blue or Purple (for SWG and high TDS) vs. Proteam MM (plain HEDP) or even the sulfamic acid vs. citric acid treatment considerations
 
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