Is it possible to intentionally convert CYA to ammonia?

epro05 · Jun 6, 2015

Regarding high CYA levels, for folks that have high water cost or have restrictions on water supply that prevent draining/refilling, I'm wondering if it is possible to intentionally introduce the type of bacteria that converts CYA to ammonia, then when that's done, SLAM to get rid of the ammonia, then add back an appropriate level of CYA.

Seems like that could be an alternative way to resolve extremely high CYA levels.

Your thoughts?

Donldson · Jun 6, 2015

It seems like the specific bacteria we run in to likes it to be cool and dark with zero FC. Most places that are under water restrictions do not close for the winter so the pool never gets cool and dark. And someone can correct me if I am wrong, but wouldn't the amount of ammonia that is created be directly proportional to the amount of CYA consumed? If we are talking CYA levels over a hundred it seems as if the cost of chlorine to remove the ammonia would outweigh the cost of trucking in fresh water.

As far as I know there have been 2 products designed to reduce CYA. Melamine has been marketed as CYA reducer in the past. Melamine is the same chemical used for the CYA test and combines with CYA. The idea was that it would bind with the CYA and then fall to the bottom like floc for CYA. Like floc, it rarely worked well and often just ended with a cloudy pool and has fallen out of favor. The latest, Bioactive, is underwhelming at best.

chem geek · Jun 6, 2015

As noted in the thread Degradation of Cyanuric Acid (CYA), if you have bacteria convert CYA into ammonia then for every 10 ppm CYA it takes roughly 30 ppm FC to get rid of this ammonia. So this is a heck of a lot of chlorine that would be needed if 100 ppm CYA turned into ammonia that required 300 ppm FC to be added.

Also, as demonstrated by the (mostly) failure of the Bio-Active CYA Reducer product, it is not easy to coax bacteria to do what you want, when and where you want it.

jkusmier · Jun 7, 2015

Richard, I'm presently slamming my pool to eliminate white mold. Long story, I had the liner and all white goods replaced about a month ago, then replaced the mesh cover as we were traveling for a couple of weeks and didn't want the pool exposed to neighborhood kids (and a pair of ducks that had been visiting the pool). Evidently I have a poor memory and didn't set my IntelliChlor to generate at the appropriate level while I was away. Removed and cleaned the cover and when I vacuumed later that day I realized I had an obvious white mold problem. CYA is 70, been brushing, vacuuming, backwashing, monitoring with my Taylor 2006 and dosing as needed for the past 24 hours. Also removed the SAm from its niche and opened the valves for the laminar jets, so all lines are circulating. Haven't tested TA yet but I'm confident it's over 60, hopefully there is a silver lining to this mess and I can get it to 60 after aerating with the jets.

Am I right to assume that since white mold is a fungus, I need not worry about CYA degradation and ammonia to eliminate with additional shocking?

Am I missing anything on my approach to the white mold, aside from testing for overnight drop?

Finally - no indication of pink slime. Assuming FC is below shock levels for my CYA level, is it safe to swim if there is mold is still present tomorrow? I've read that pink slime can cause health risks, but none about white mold.

It's been awhile, I hope you are well!

-Joe

chem geek · Jun 7, 2015

There are some fungi that can also degrade CYA, but more slowly than soil bacteria. I wouldn't worry about it and there's nothing you can do to prevent it other than killing the organisms which is what you are trying to do anyway. For white water mold, a SLAM is the right approach. Once the white mold is established, it takes a while to kill off, but getting behind niches and exposing with SLAM levels of chlorine will get rid of it.

White water mold isn't a health hazard but it could be slimy so if it's on pool surfaces you step on then that could be dangerous. If it's only a smaller amount in selected areas, you could swim below SLAM levels, but you shouldn't let the chlorine drop too much and should raise it back up as soon as you are done. Sustained high levels of chlorine will kill off the mold. You can physically scoop out larger pieces of it (grabbing by hand usually doesn't work as it falls apart like tissue paper).

jkusmier · Jun 7, 2015

Thanks! Quite clear today, only saw a couple small pieces floating below the surface. Vacuumed this morning, and again after kids had friends over. Water was a little cloudy afterward but there were 6 kids in the pool. Hit it with a couple more jugs of bleach via skimmer. Hopefully it's gone tomorrow, I'll test FC and CC after work and probably hit it one more day.

poolnoob.ca · Jun 8, 2015

I believe its not recommended to pour bleach in the skimmer to prevent equipment damage?

chem geek · Jun 8, 2015

Yes, it would be better to add the chlorine over a return flow (usually in the deep end) with the pump running. Adding it to the skimmer isn't great for several reasons. The high chlorine level will be slightly damaging to equipment (but it's at high pH so not as corrosive) and will oxidize organics in the filter creating more disinfection by-products (normally you'd clean the filter to remove such material before some of it reacts with chlorine).

It is far worse to add anything acidic to the skimmer so Trichlor tabs or powder is a definite no-no, most especially if the pump isn't running. Dichlor and MPS through the skimmer also aren't great, though not as bad as Trichlor. Chlorinating liquid or bleach is the least problematic of these, but it still is not a great idea, certainly not to do regularly. Other chemicals such as baking soda are not a problem in the skimmer, but quite frankly nearly any chemical can be added slowly over a return flow with the pump running to cause the least problems. One should brush the pool surface in the area where one adds a concentrated chemical just to ensure thorough mixing (this is most especially true when adding acid as that can pool at the bottom of the pool if one adds it too quickly).

jkusmier · Jun 9, 2015

You're absolutely correct, and I know it's not best practice, although I rationalize it by pouring slowly and not doing it regularly. This is my 7th full season and after working my way through the learning curve in the first season with TFP and poolandspaforum, I shock an average of 2-3 times/year after opening. I'm also careful to disable the IntelliChlor before shocking.

There are worse offenses, in the beginning I would add Biogard silk sticks to the skimmer, then moved on to pucks (only while pump was running), but won't ever do that again. The only other thing I add to the skimmer is CYA, in a skimmer sock. No baking soda this year, after replacing liner and filling with city water my TA was 260! Been aerating and adding acid every other day and it's down to 140 now, aiming for 60 by this weekend. When I reached that level the last two years I was amazed at how little pH creep I saw, even with the salt cell.

All things I'm very grateful to have learned here. I used to chuckle to myself when standing in line at the pool store while watching pool owners leave with armfuls of stuff they would almost never need if they'd done some research and taken control of their water chemistry. Later I simply scratched my head. Now, I'm happy to say the only things I've bought at pool stores in the past 5 years or so are liquid chlorine, vinyl cleaner, o rings, eyeballs, skimmer socks and a skimmer pole - and even then only when I had an immediate need and couldn't wait to order it online at a better price.

Finding the white mold was frustrating but I'm confident it's gone, CC was zero this morning and again this evening. I'll let the FC drop over the next couple of days and then enable the cell. But I'll keep a couple of jugs of bleach in storage just in case...