closing pool and pH

[EmilyOTR]

I asked this last year but my pH is higher this year - I'm at 7.8 and they are coming to close tomorrow. I'm out of acid, do I need to do anything?

 

[Catanzaro]

All depends on your cover and what usually happens to your PH over the winter. Is your PH lower upon opening the pool, or it is higher than what you normal close with? Do you have rising PH issues during the summer? If so, then I would lower the PH back down to the 7.2-7.4 range. My PH drops through the winter (only thing I can think of) is the solid cover (no breathing room), so I bring mine up to around 7.8 before I close, and it is usually in the 7.5 range all summer long.

 

[EmilyOTR]

we have a solid tarp cover. this is only our 2nd year. when we opened this year the pH was very high. Our pH does rise during the summer quite a bit.

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and if I need to go buy acid, I'll have to buy 2 jugs. will it be ok outside in a deck box or shed all winter? I'm in Michigan it gets very very cold here.

 

[Texas Splash]

The acid will be fine over the winter and ready to use next year. Just store separately from anything else metal. Corrosion. Don't ask me how I know.

 

[EmilyOTR]

What should my pH be at closing? It was over 8.2 when I opened this year.

 

[Texas Splash]

What should my pH be at closing?

Unfortunately, there is no one perfect answer for everyone. As Cat recommended above, probably best to lower your pH to about 7.2-7.4. That is based on the expectation that your pool's pH seems to climb quite a bit over the winter. If you feel adventurous, you can experiment with the PoolMath tool and experiment. Enter your current pH, TA, CH, and water temp. Then look at your CSI number. Ideal is slightly negative, but there is some wiggle room. You expect the pH to climb in the winter, but you also expect the water temp to drop as well. So try entering some reasonable (new) numbers for projected water temp and pH. Example 40 degrees and 7.8. Since you expect the pH to be excessively high (8.2 or above), then lowering the pH to about 7.2-7.4 now seems like the prudent choice.