PH 8 or possibly higher

[Janeen]

Happy Saturday Morning, starting weekend with PH 8. We admittedly haven't been consistently testing PH. Last test prior to today was 3-4 wks ago = 7.5. We only use bleach on a daily basis. We test FC 1-2 times per week, it remains within proper limits 4-6. I have 3 questions:

What causes the PH to jump? - is it from the bleach or other factors?
How do we prevent it from happening? - test more often lol, anything else we need to be doing?
Is it ok to use pool store PH down instead of MA? - need some alternative to MA, will not allow it around our home

Today's results:
FC - 6
CC - 0
CYA - 50
PH - 8
TA - 90

Sincerely,
September problems :-o

 

[pooldv]

It is important to maintain PH between 7.2 and 7.8 at all times. High ph can lead to scale build up in the pool. It is ok to use PH down in place of muriatic acid. It costs more and will cause sulfates to build up. Although I'm not sure what the negative side effects are in a vinyl pool.

 

[Divin Dave]

Hi Janeen,
As pooldv says, it's ok to use pH down from the pool store. I dont think there will be any side effects of it since you have a vinyl pool.

The chlorine isn't causing the pH to rise. pH rises for a whole host of reasons . The TA in your pool is a buffer to pH rise. Everything being equal, typically the higher your TA, the quicker the pH will rise. The lower the TA the slower it rises. Of course not everything is always equal that there are limits as to how low can go. Since no pool is exactly like another and doesnt act the same, is the reason for such a wide range of the recommended TA level.

Since you have a vinyl pool, if you were to lower your TA, it most likely would slow down how quickly the pH rises. Maybe something in the order of 70 to start with, then monitor pH for a while and see how that does. If you needed to, you can adjust it even lower to help more, but I wouldnt recommend going lower than about 50 with your TA.