Just joined the group, but I wanted to share my results from using Bio-Active.
Background: I bought my house in Oct 2015. 14,500gal pool, pebble tech surface, It had a CYA level of 156. They told me not to worry about it, use liquid chlorine over the winter and the levels will go down on their own with the rains.
Being a new pool own, I was think Ok. I did a bit of research and found Bio-Active as a possible solution. I wanted to see if 'Nature would take care of it' well we had slightly wetter the usual (but not too wet) winter, and it did drop some, down to 136, by the beginning of April. Water temps where coming up, and I wanted the CYA down, so I bought an 8oz bag on amazon (Water Temp in the 70-75F range, Ph 7.4-7.6 range, Ch kept between 1.0 and 2.0 with liquid chlorine, no tablets, no clarifier, no fusion cartridge installed...)
After 10 days, it dropped from 136 to 133. I contacted Biowish about it, and got no response after two weeks, other than they would get back to me shortly. So it was time to write a review on Amazon I posted my results. They promptly contacted me after this, offered to send out their commercial sized bag of Bio-active (16oz) which I tried. I provided them all my chem levels, temps, etc and followed their instructions to a T. The results, where no significant changes after another 2 weeks. So I decided to move forward and forget about Bio-active. I will say that the CYA went down a little over the summer, not sure if it was residual Bio-active in the pool or not, because we didn't have rain, and I was using Trichlor tabs (35lbs worth from May-Sept end) it was at 120ppm at end of Sept. after that I went back to liquid chlorine over the winter, which was record breaking in terms of rain, and had the pool overflow a couple of times before I bought a submersible pump to pump it down a bit when raining (no backwasher, no output plumbing switch to drain) but it did manage to get the CYA down to around 80ppm.
Now comes in the question, there's been speculation that the Bio-active can stick around for along while and keep eating the CYA slowly instead of fast. Did this happen to mine over the summer? I don't know, there may have been some impact from that, but after effectively 3x what's required for a 25,000gal pool (8oz bag is supposed to treat up to a 25,000gal pool) in a 14,500gal sized pool. And the expectation of significant reductions in CYA within days, it definitely did not work as advertised for me personally.
There are a number of success stories, and I'm happy for them. I don't think Biowish has figured out what the difference is that makes it work great for some, but fail miserably for others.