Does Ca hardness contribute to ph drift?

[djhop5]

I have read many of the threads on ph drifting upward and how it is affected by TA level, etc. My question is, does a calcium hardness level that is low enough to render a csi of -.6 or so contribute to ph drifting up from 7.6 to 7.8 every couple of days? Or, does calcium hardness and csi value have nothing to do with it and it is just that TA is still a little high for my pool? I know that low csi in vinyl pools isn't as critical, I'm just wondering about its affect on ph drifting up.

18k gal vinyl, TC 5-7, ph 7.7, TA 60, CaH 100, CYA 40, no added borates, salt from bleach use only (non swg pool), 6hrs sun

 

[mknauss]

CH levels have no direct effect on pH. pH stability is tied to Total Alkalinity.

pH rising is tied to aeration and TA level. Most water tends to look for a pH balance of 7.8 to 8. Do not adjust your pH until it reaches 8.

 

[djhop5]

Thanks Mknauss. That answers that. I've been wondering about that for a while. I have been leaving ph be until about 8, then lowering by point 2 or so.