CYA help please!

[macox126]

Adminitrators, thanks for the posting help. Opened pool for the first time after installation last year. CYA got away from me last year until I was blessed with finding this forum. It was 200+ toward the end of the season using tablets only and I changed out water slowly and made good progress lowering CYA by the time to close. At closing I was using liquid bleach only. Let the installer close due to cover installation and they did lower water somewhat but it is fiberglass and water table is high. Let installer open pool as I wanted to observe procedure. They put in 3 or 4 tri chlor tabs into auto dispenser. After check with Taylor test kit, FC was 2, 4, and 2 the last 3 days. I have added 1 gallon 10% sodium hypo each of the last three days. CYA is under 30. Can see black dot clearly, just smaller at the 30 level. How should I increase the CYA and to what level? Water looks very good. FYI - pH = 7.2, TA = 130, CH = 310. Last year pH was running 7.8 give or take. Thanks for any advice.

[BigDave]

If you have a supply of trichlor tabs and the trichlor is maintaining adequate FC, you might as well just use the tabs until you get your CYA where you want it then switch to bleach (liquid chlorine). Keep an eye on pH because the trichlor will cause it to drop and your water's already at 7.2. Raise pH with borax so the TA won't climb.

[CarlD]

To give more detail to Big Dave's advice (which is sound), I don't like CYA to be below 30, and generally don't like it to go over 50, because there your maintenance level of FC is 3 to 6 ppm. But, if you find at that level of CYA you are adding chlorine all the time, then by all means raise it to the 60 to 80 level and maintain FC at 5 to 10 ppm.

[macox126]

Thank you sirs!