I have a 6000ish gallon fiberglass pool. I chlorinate with 8% bleach and have done so for years. This year my alkalinity refuses to stay in the 100-110 rage that I try to keep it in and my PH always seems to move up to 8.0. I've never tracked CH but I just tested it and it is 40. Any suggestions? Water tastes somewhat salty. Should I just let the ALK drop down to where ever it wants to go? Any suggestions on what could be causing this?
Continual declining ALK and increasing PH / 6k fiberglass pool
- Thread starter keithw
- Start date
Yes, when PH gets to 7.9 or 8.0 lower it to 7.2-7.5 with muriatic acid. This will slowly lower your TA over time. At some point your PH should stabilize. It is fine to let your TA drop as low as 60.
Any idea what could be causing this shift? Old water? Weird bleach? I have never had this problem before. I have used almost 3 gallons of muratic acid this summer and that is a lot for a 6k fiberglass pool. I guess I will stop increasing the TA and just concentrate on the PH for a while and see where the TA ends up.
Didn't catch that was a new this year problem in the first read. My first guess would be a TA change in the water supply. Have you tested your fill water? Maybe the TA is lower for some reason.
You may have more carbon dioxide outgassing occurring from greater aeration (including from summer rain), from higher temperature, from longer pump run times or more pool use (splashing, swimming), from more wind (if water gets churned), etc. Or you may have stopped using net acidic forms of chemicals such as Trichlor or Dichlor or non-chlorine shock. 100-110 ppm TA is on the high side for pools and there is no reason for you to try and keep it so high.
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