Lived in this house less than a year. Pool was built around 1999. Has not been well taken care of i think, all the gelcoat is gone, surface feels rough below waterline and smooth above it. But thats another story. I have really high CYA. I tried using Bio-active CYA reducer from my local pool supplier. She suggested using 1/4 of a bag at a time to slowly bring it down as to not bottom it out with a full dose. I used a 1/4 the first day with no results. 1/4 next day with no results, 1/4 bag on the third day moved the needle a little but was barely noticable on test strip. used the last of that bag on the 4th day and was still high but much more noticeable change. waited a few day and CYA was back up so i went and got another bag and said screw it, dumped about half of it in. next day barely noticeable difference, next day dumped other half bag in and finally got it down where i thought it needed to be. 2 day later it was back sky high off the chart. Any idea what could be going on ? Only other issue to my knowledge is the poo leaks but i dont lose any water. There is a place in the shallow end that has been repaired in the past. the pool floor is uneven and feels like its got bubbles of water under it maybe. when you walk around if you kind of work those bubbles towards the repaired area you can see cloudy water shoot into the pool water from where there is an obvious crack. In the deep end of the pool s a place that is bulged out and cracked also. if you push on the sidewall of pool above this area you can see dirty water shoot into the pool water from this crack also. I've obviously got issues but I hardly ever have to add water.