Constant PH rise

[botanica37]

This season, my PH is constantly creeping up to the point that I am adding muriatic acid every 4-5 days. I am using 6% bleach only and I read somewhere that the bleach PH is 13 so it would raise the PH somewhat...but then reading through the forum it seems that people are using bleach and not having the issue with the PH going up. Any thoughts/advice?

FC 2
CC 0
PH 7.8 (yesterday 7.5, the day before 8.2 lowered with MA)
TA 90
CH 260
Borates 30
CYA 35
Temp. 78

Thank you!

 

[257WbyMag]

Bleach is inherently basic so your pH will rise with its continued use. You might try lowering your TA some more and see if that helps to reduce the frequency of which you need to add MA.

I have to add MA about every four days too.

 

[frustratedpoolmom]

Interesting... how old is the plaster?

Do you have an autofill? Is your fill water high in PH or TA?

What about any other sources of aeration, water features, fountains?

So I can assume your TA is gradually getting lower with the acid additions? Eventually the PH should stabilize as you get the TA around 60-70...

 

[botanica37]

The plaster is about 4-5 years old I believe - the previous owners had the pool replastered, so I am not exactly sure of its age. Interestingly enough my TA is stable - it has been at 90 since I opened the pool couple of months ago and I test it weekly. There are no water features, and the only water movement is from the returns on the bottom with the Caretaker and spa overflow.

 

[frustratedpoolmom]

Spa overflow may contribute. If the TA is steady with acid additions, that means your TA is going up from somewhere.... autofill?

 

[botanica37]

I don't have autofill either...Maybe the aeration from the returns with the Caretaker is to blame? But then why would the TA stay steady at 90? Shouldn't it keep climbing too?

I think I will lower the PH again and test the TA maybe 2-3 hours after adding MA?

 

[frustratedpoolmom]

Sounds like a plan.

Aeration doesn't raise TA. It has to come from another source, like fresh water being added that is high in TA, or baking soda additions. I don't know how the caretaker works. Does it introduce air/bubbles into the water?