This is my 3rd summer in a new house with an inground pool (est. 30,000 gallons). I have been using the TFPC method since I moved in (I think it was called the BBB method previously). I never had any CYA in the pool which I thought was strange b/c I think the proper owner used the pucks. I had been putting 121 oz. of bleach in the pool each day for the last two years which would keep my FC levels at 2ppm by the next morning. I decided to try CYA about two weeks ago and added about 13 lbs of it, which raised the levels to 50. And now I find that if I add only 60oz of bleach, it will keep my pool above the recommended FC level of 4 for three days. That is a drastic change and while I am pretty confident in my testing ( i use the TFT kit recommended on here), I guess I wanted to see if that sounded reasonable to the more knowledgeable people on here. Also, I drain my pool just the below the returns in the fall, should I expect to lose most of my CYA by next spring?