2 Weeks ago I got my pool temperature >70 deg, pH to 7.4 and FC to <4. I put my first bag of Bio-active into the strainer and ran the pump for 4 hours. The problem with the first round was that I never did a diluted test to find a value, besides >100, for my CYA. I tested at 72 hours and 10 days. I had the local pool store verify my end results and it was still >100. Because I didn't have a good baseline I thought that my CYA was just astronomical and would give it another shot. I paid $53 for the first bag.
For the 2nd go-round I wanted some more solid numbers. my pool was 73 deg, pH 7.4, and FC was 0.5. I believe they suggest a FC of 2-3, but I thought a low FC would give the product a better shot. I came up with a CYA of 140 (using a 1:1 dilution) and got the pool store to declare it at 110. Somewhere I read that a CYA of >100 has a margin of error of ~30. I knew that I would need to take that into consideration. I asked the pool store to give me a break on a 2nd bag and so they charged $36.
I added the Bio-Active that afternoon and ran the pump for just short of 4 hours. The pump was going to turn on again by itself for four more hours later that night, so I figured I was OK not running the full 4 hours. I tested the water after 71 hours and with a non-diluted test came up just short of my 100 mark for CYA. I'm guessing it was 110-120. I had 7 mL remaining in the test bottle so I used a syringe to add 3.5mL of tap water to the pool water and reagent and tested again. I hit 70 on my Taylor tester. With a 1:1 dilution that would put the CYA at ~140.
Like many of you, I was really hoping that this was going to be a revolutionary product. I really feel like I gave the product a legitimate shot. I'm going to send a link of this thread to the manufacturer and see if they can point out something that I did wrong.