Should I fix my TA?

[keithw]

Just wondering if I should fix my TA or disregard. Here are my specs.

6K gal fiberglass.
CL 15PPM (just shocked it, letting it creep back down to 5-6PPM)
CYA 50
PH 7.2
TA 220

Everything seems fine in the pool. I plan on putting my winter cover on in a week or two.

[chem geek]

You can disregard it. Your low pH compensates for the higher TA, but even if your pH were 7.5 you would still be fine. The only issue you *might* be seeing is a tendency for your pH to rise unless you keep your pool covered most of the time. The reason is that the low pH, high TA combination will tend to outgas carbon dioxide and that causes the pH to rise. You would then have to frequently add acid to keep the pH low. Eventually, this will lower your TA over time. Is that what you are seeing? Perhaps your fill water is high in TA so is keeping your TA high (if you backwash frequently, for example).

Richard

[keithw]

Actually it seems like my PH has been drooping vewry slightly. It was 7.5 a few weeks ago. I had dropped a cover on the pool. The TA is hight because I keep adding baking soda. Keep thinking that it's baking soda that increases PH!

[chem geek]

OK, but you now know that it's [EDIT]washing soda[END-EDIT] (aka Soda Ash aka Sodium Carbonate) that raises pH as well as TA. Borax (or Caustic Soda aka Lye aka Sodium Hydroxide) will also raise pH without significantly raising TA. Baking Soda (aka Sodium Bicarbonate) raises pH a little, but mostly raises TA.

As for the pH drop, that is strange though you did say you were shocking your pool and letting the FC drop. When you first added the chlorine to raise the FC, then the pH would have gone up and as the FC drops with the chlorine getting used up the pH will drop. Any other changes in pH you see are due to other sources.

Thanks for the info. At any rate, you can close your pool with your current TA with no problem. I would check the pH and FC levels remembering that the pH will continue to drop (a little) as the FC gets used up so you don't want it starting out too low.

Richard