Drained and refilled - adjusting alk and calcium

[duraleigh]

Hi, Richard,

I'm not sure we're too far apart. My thinking was sanitizer in the pool as a priority and some acid to get the pH in the 7's. Then adjust Alk and Calcium.

It sounds like I may be underestimating the urgency for Calcium and Alk. Are you saying you would address them first?

[chem geek]

Yes, we are in agreement now that I understand your priorities you were describing. I absolutely agree that getting the sanitizer level up (i.e. adding chlorine) is first and foremost in importance. I would also add the TA and CH very shortly thereafter as it is also important, but not quite as time-critical.

I don't believe the pH is as critical since the higher pH actually makes the water less corrosive and "buys time" until the TA and CH are adjusted. The chlorine is most important, but the pH, especially a high pH, is not a problem at all when the TA and CH are so low. Once the TA and CH are added, then the pH can be adjusted. If the pH creeps up too much and/or the water gets cloudy when adding the TA and/or CH, then the pH can be lowered with acid before more TA and CH are added.

Richard

[duraleigh]

but the pH, especially a high pH, is not a problem at all when the TA and CH are so low. Once the TA and CH are added, then the pH can be adjusted. If the pH creeps up too much and/or the water gets cloudy when adding the TA and/or CH, then the pH can be lowered with acid before more TA and CH are added

That makes good sense and helps me understand that relationship a little better. Thanks.

[dhale1]

Thanks for all the replies. My pool was not replastered, just acid washed and a couple small patches. I went ahead and added calcium yesterday morning and a quart of polyquat 60 last night. Anyway, here' s my numbers now.

FC 3
CC 0
TC 3
PH 7.4
CH 130
ALK 80

So, my next question is: Should I get my calcium up to 200? The guy at the pool store said that since I was closing my pool next month that I should leave the calcium where it is until next year. I said I thought that it needed to be between 200 and 400 and he said not for the winter. He told me if I get it up to 200 then there's more chance for scale to form over the winter since the water is not circulating. Any thoughts?

[duraleigh]

I think I would bring the calcium on up to 200. Scaling will occur only if you lose your grip on pH and Alk and you seem to have a good handle on that. I believe the calcium requirement for a gunite pool is year round. Perhaps not as much in cold weather but I see no harm in bringing it up now.