Bio-Active 100% Cyanuric Acid Reducer for Swimming Pools | Non-Toxic CYA Reducer Powder | 16 oz. | 1-Pack

I used this to reduce the level of the UV protection in the pool. It had gotten so high the chlorine wasn't doing its job even when the residual level was high. The other option I knew of was to partially drain the pool and replace the water which is more expensive and a waste of water. I have what I consider a normal sized pool and it only took half a bag. After you add it wait a week or so to test. It is not an instant thing.

Highlights - worked to reduce CYA from 270 to 150. I was very excited that this was going to work to bring the pool back to a manageable level so the chlorine would work again at appropriate levels. I followed the instructions and found it worked, but as others have reviewed the chlorine becomes useless after treatment. I added approximately 8 gallons of liquid chlorine over two weeks to maintain Cl levels. Each week about 6-7 days after shocking the pool was green. I did this for several weeks and attempted to add 4 gallons of Cl and measured it about 8 hours later and the Cl level was zero! Whatever is in my pool kills the chlorine. I had to drain and clean filters, whatever algae is now in my pool is very hard to kill. Details of treatment: I have a 25,000 gallon pool in Phoenix Area Continuously and added Cl (chlorine) and Ma (Muratic acid) to maintain chemistry within the instructions and measured each day. 07/15/24 PH 7.4 Cl 2.0 TA 110 Cal Hard 610 Water temp 91 CYA 270 using triple dilution in Taylor dropper test kit (not strips). Added 16 oz of CYA reducer 07/16/24 Saw a spike in ph after adding PH 7.8 Cl 1.0 7/17/24 Ph 7.6 cl 1.6 CYA 240 Added MA and Cl 16oz 7/18/24 Ph 7.6 cl 1.8 CYA 210 Added 8oz ma 16oz Cl 7/19/24 Ph 7.4 Cl 1.7 Cya 180 7/20/24 Ph 7.4 Cl 0.8 Cya 165 Added 16oz of Cl 7/21/24 Ph 7.4 Cl 0.2 Cya 150 Pool turned green. 7/22/24 No test Added 1 gal Cl to shock and complete CYA reducer treatment. 7/23/24 Ph 7.4 Cl 5 CYA 150 7/24 Ph 7.4 Cl 1.1 Added 16oz Cl

This product actually worked! My 20,000 gallon inground vinyl pool had a CYA above 260 for the last several pool checks prior to closing it down last year in late October 2025. The Leslie's rep said I would need to drain it by half and refill. This year, opened the pool, and the CYA was still above 260 at first water check at the beginning of April 2026. I picked up a 16 ounce package of this acid reducer and added to the pool water. The chlorine levels were nil, none in the pool. I let the water circulate 24/7 for 2 weeks straight. Today, I took a water sample over to Leslie's and it was 139. I couldn't be happier. No need to drain down the pool. Which is a good thing, since we are currently in a moderate drought condition. The one drawback, the shipper sent me a package that was 2 months past it's best by date. I can't help but wonder if I had received one that had not expired, if my CYA would be even lower.

Okay... I've read the reviews and tried this last year. Here's the real deal. It 100% can work. It dropped my pool from 190ppm to 20pm. I use a Taylor kit to measure CYA so it's as accurate as anything non lab. 22k gallon pool. How it works. This is not a chemical. It's a living bacteria that through its biological process can convert CYA into something else which I believe is ammonia. How to use. Knowing that it's alive... your pool cannot contain chlorine when the product is added. I know it says 1-3ppm but that's not going to work as it destroys the product. Use chlorine remover if needed. The water needs to be warm if possible. I did this after labor day when it was too cold really to swim but still warmish. Mix the product and follow the directions to add it. Now... wait. I mean it. It takes a LONG time. I left the pool open and green until it got cold and the algae started to die on its own. I closed the pool as it was. I couldn't help it but I tested the CYA and found it to be around 120. It did work... but it was still too high for my goal. When I opened the pool it actually wasn't very bad. I can only assume the organisms ate the algae as it had zero chlorine. A significant amount of dead algae, which looks similar to sand was on the bottom of the pool. I tested the water for all factors... everything needed adjustment but CYA was around 50. I had won. At this point I was ecstatic. The part they don't tell you... this organism makes what I believe is ammonia from the CYA. Ammonia destroys chlorine at an alarming rate. I added a super shock of cal hypo and brought it to 15ppm. The next morning it was zero. I did this again. Zero next day... I've never had chlorine leave my pool so quickly by any stretch. I knew the game though. You MUST hold the ppm around 15 whatever it takes or the organism can keep multiplying. It's like fighting algae except this organism can destroy chlorine. I bought 8 gallons of liquid when I realized I would deplete the cal hypo. I kept testing and adding cal hypo and then liquid until the rate of loss slowed. After about a week I could hold the chlorine around 8ppm with a "normal" addition. I was out of chlorine though... 15lbs and 8 gallons would normally last me a couple months but it ate it in a week. You need to be ready for this. If you allow the ppm to drop the organism will regenerate and you start over basically which obviously gets expensive fast. Just trust the process and test/add at least twice a day. Trust me when I say you want 15ppm at least. Nobody is swimming so it won't hurt a thing. Heck 30 would be better. Whatever you pick make sure to hold it there until it doesn't drop quickly. Now... at this point the water should be clear. Vac the algae dust and balance the other factors. Notice I didn't do that until now. Lower ph helps chlorine work. Balance as you normally would probably needing some ph up. Keep in mind with lower CYA it will drop chlorine faster than you are accustomed but nowhere like that first week. Enjoy the pool and make sure you never use stabilized chlorine ever again. Liquid is best as it's pure chlorine with water only. Cal hypo is next best but has some downsides. If CYA is too low you might need to add a bit but let's not undo all that work. I believe 30 is plenty. I know it sounds like a lot and it is but is better than draining and refilling 22,000 gallons. Another note... hopefully the manufacturer reads this. My sealed 16oz bag had only 8oz. I have a quality scale and calibration weights. I only measured it because it felt light. I know what 16oz feels like and this wasn't it... turned out I was correct. I was very upset at first but now that it has worked all is forgiven. That said... please fix this as it appears to smudge the reputation. I originally made a very poor review that amazon denied. I still have a video of me weighing the sealed bag to backup my claim but as I said I no longer wish to make a problem of it. I took a star away due to this and the lack of complete instructions like I gave here. If you read other reviews you will see others have had similar experiences. A final note. After all this I ended up going salt chlorine generator. I highly recommend one. I've literally done almost nothing to keep my pool clean this season. With the high CYA I was fighting algae constantly for two seasons. This season with low CYA and SWG I just run the pump ~8hrs a day and add some acid every few days. Vac from time to time. It's crystal clear and I'm done buying chlorine. If you are on the fence, do it. Buy a SWG rated for twice as many gallons as your pool. Another somewhat problematic thing... but yeah they are not rated properly. Go higher. Thanks for reading and I hope you find this helpful.

Natural chemistry products are usually high quality however this cyanuric acid product is not one of them. It's worthless. I tried the 8 oz. sized pouch the previous swim season but I had just added their "no-phos" product and then read that it interferes with the performance of the cyanuric acid reducer so I assumed the poor results were my fault. This season I tried the larger sized 16 oz. bag and did not add "no-phos" or chlorine from 7 days prior to usage and I also waited for the weather to warm up to 70 degrees and over as prescribed in the instructions. Results were the same this season as last season which were none. No reduction of cyanuric acid was achieved. Do not buy this expensive ineffective product. I had my pool water checked at the local Leslie's Pool Supply who used to sell this product but they also confirmed that it doesn't work.

It seemed to work fine in pool I had before I sold my house that had a pool. At least CYA level dropped after I added some of it to the pool.

I waited quite a few months to write this review, mostly because of the mixed reviews I had seen before buying the product. I do want to tell you that IT DOES WORK, but it takes time, even more time than the manufacturer quotes. I first put the product in my 9,500 gallon pool (dose adjusted to match the size of the pool) in early August 2024 and my CYA was at 57ppm. A week later my CYA had gone up by about 2 ppm to 60ppm (likely because the CYA was being etched off the pool surface), but then it started a slow decline over the following weeks, In November 2024 it was at 44, now in February 2025, it has stopped dropping and has held at 29ppm. I have not drained the pool and refilled at all, any filling has been the autofiller adding water that has dissipated from use or evaporation. Does this product work - YES. Does it happen as fast as most people might like - NO. But now knowing how it works now, I'll just start using it earlier before my CYA gets out of control knowing that it will work, it just will take its time to do so. I think its an excellent way to return your pool to pre-summer CYA levels after the pool season is over knowing that the DiChlor is going to cause CYA to rise over the following summer.

WASTE OF MONEY! Product didn't work even though it was applied according to directions. The item received was manufactured over two years ago, and maybe this affected its effectiveness. Water tests done at Leslie's. Ordering the pouch type that really works.