Bio-Active BA-CAR-16 Non Polluting 100-Percent Cyanuric Acid Reducer Powder for Commercial and Residential Swimming Pools, 16 Ounces

Worked as expected - will need another bag though, have just a bit more to go before I reach the right number. When I purchased, my CYA was around 300 or more (lets put it this way, I was way passed the 100 mark on the tube) - I have a 10k and the bag says it will treat up to 25k ... well, I am now at 100. So, it works, but you may need more than one bag depending on size of pool and amount of CYA in pool. Also you should note that it can take up to 10 days to lower your levels - so I will have to wait another 6 days before adding a second bag to be sure.Leslie's charges $49.95, so this is a good price.Now, this wasn't the only thing wrong with my levels, so how it worked for me, may not be what you need (and I suppose I won't really know if it works until I add the second bag and see if it drops to where it needs to be)How I did it :I took out my chlorine duck and let the pool do it's thing (running 8 hours a day) for about 10 days with no chems.Then I washed my filters thoroughly and added the Phos Killer (from walmart $9 - kills 1000 ppm) and ran the pool for 48 hours non stopThen I turned the system off for 24 hours and let the pool sitAfter 24 hours I washed my filters again and then added my duck back into the pool and let the pool run a normal cycle for another day before FINALLY adding the whole bag of CYA into the skimmer and let the pool run normal cycles for 72 hours before adding the Alkaline Up - then ran it for 12 hours and when I took my water to be tested everything was back to normal except I'm now at a 100 on my CYA rather than 300, so if after 6 more days the levels aren't where they need to be, I think one more bag should do itThis is the information I was given about using the Bio-Active product:::Bio-Active uses natural cultures to reduce your CYA, be sure your pool will be habitable for the the organisms to do their job. You should also not that your chlorine will attack these organisms, so it's best to be in normal or low ranges. In addition to providing livable ranges for the active ingredient to thrive in, make sure you take note of the information below to get the most out of each dosage:» Do not add shock or algaecides 7 days prior to application.» Works best in an outdoor pool, uncovered for at least 7 days.» Bio-Active does not work in mineral system pools.» Make sure your pool is free of algae or other contaminants.» Be sure to shut off UV, ozone, and chlorine feeders 15 minutes prior to, and 3 hours after, applying Bio-ActiveSafely lowers CYA levels within 10 days without needing to drain the pool.Eliminates chlorine lock due to high CYA.Use 1 bag for up to 25,000 gallons.Works best with water over 65 degrees Fahrenheit.I hope this helps anyone having troubles - I know it's a bear of a situation and VERY time consuming .... Don't you remember going to the lake and swimming or fishing, never once thinking of what microscopic things lay in wait? Having never once thought of PH levels or the like? We lived, didn't get sick and kept going back (this is in no way meant to diminish anyone's adverse reactions to such events - merely a personal reflection). Do you think lake or ocean water is cleaner than your pool? Yet here we all are, busting our hump, spending hours and hundreds of dollars even when our pools are sparkling clean and we can't see anything wrong (as is my case - before all this process I mentioned, my water was clear, had no odor and looked great ... but it had been a while since I'd had it professionally tested and wasn't sure if MY test stuff was still optimal, so I took it in and BAM! There was evil lurking in that falsely serene setting of a sparkling pool ready for swimming. Sounds fishy to me, but - here I am, tired, annoyed, poorer and ready to just fill it in and plant grass!

Wish I could say this had no effect. It has actually had a negative effect. I now find myself in the same situation Amir did.I bought one packet of this stuff at the beginning May. My CYA levels were high - between 100 and 150 ppm. I figured might as well give it a shot. Against better judgement, I ordered a packet of this stuff even after seeing the average rating sucks - because my pool guy recommended it. The first packet did absolutely nothing. My chlorine level, pH, total alkalinity and water temperature were all perfect prior to adding the packet. I ran my pump 24/7 after adding the packet. I saw absolutely no drop in my CYA level. I should have stopped there. But I figured what the hell, I'll give it another go. I added another packet 9 days ago. Again, my chlorine level, pH, total alkalinity and water temperature were all perfect prior to adding the packet. This time around, I saw my pH drop drastically within a day of adding the packet. In 3 years of owning my pool this has not happened once to me. And then I saw my chlorine level bottom out completely. My pool became cloudy. I thought it was due to low chlorine. I live in Colorado - liquid chlorine is not readily available. I called several pool shops in the area - no one carries it. So I bought a bucket of calcium hypochlorite. I began adding small amounts to my pool to try and bring the level back up. I have a chlorine feeder and use tablets normally throughout the swimming season. I've never had to have my feeder valve above a 2 setting. I set it to 5. I also had replaced all valves for my feeder about a month ago. My chlorine levels would go up when I added cal-hypo, then tank back out to absolutely nothing within a day - both for total and free chlorine. My pool stayed cloudy. I was adding algaecide and super blue. Still had cloudy water. Then I decided to backwash my filter. Normally I do this every 2 weeks, and I had actually backwashed it a week early just prior to adding this crap to my water. To my surprise, absolutely no media (I have a DE filter) came out in the water when I backwashed it. Normally it leaves a little white area in my lawn where I do. This time around...there was nothing whatsoever. My filter had no media in it at all - despite being recharged a week earlier. In 3 years of owning my pool this has not happened once to me. After recharging my filter, my water finally cleared back up. But my chlorine problems remain. My regular pool people recommended going big - so I put 5 lbs of cal-hpyo into my 20,000 gallon pool. The chlorine levels were higher than I've ever seen then. And then the next day....they were right back to 0, both total and free chlorine. I've gone through about 15 lbs of cal-hypo and around 10 pounds of 3" tablets in the last 5 days and this morning when I went out to check my chlorine levels....they were right back to 0. In 3 years of owning my pool this has not happened once to me. I'm going to have to wind up draining and refilling my pool if this cycle doesn't stop.This product is not only useless, but it can actually be destructive.Please listen to other folks and don't make the same mistake I did.