PH level at closing

[mamasproject]

Hello,

Last year when our pool was closed I brought the PH level down to 7.0 because the PH levels rise quickly in my pool. After opening the PH level was well above 8.0. I remember having to put alot of muratic acid in and it took 2 days to bring it down.

Fast forward to this years closing (which is tomorrow)...I keep the PH level around 7.4-7.6 but need to put muriatic acid in every week. So my question is....should I just lower it to the 7.0 again this year and hope for the best? Or do I lower it into the 6.8 range? The pool is 2 years old.

Thank You!

 

[JasonLion]

That mostly depends on what your TA and other levels are. Could you post a full set of water test results? Also, when was your plaster installed?

 

[mamasproject]

Pool was finished in October of 09

FC....3 (at the moment)
PH....7.8
TA....50
CH...280 (low due to all the rain we have had)
Temp....around 62
CYA...around 10 (again low to all the rain)

 

[JasonLion]

With those numbers, I would only lower the PH just a little, say to 7.5 or 7.6. You could go a little lower if you want, but I would not take the PH below 7.3. If you lower PH too much you could have some etching of the plaster over the winter.

My guess is that your chemical levels were very different last year, resulting in the dramatic PH increase over the winter, though there are some other less likely possibilities.