low TA, Ph staying high

[Blake106 0]

Hi all, new to the forum. For quite a while now the TA in a pool i'm taking of is seeming to have an odd issue where the TA is relatively low (70) but the Ph just keeps wanting to go up, it is staying at 7.8 with the use of trichlor tabs at the moment. The trichlor is counter balancing the ph so it will stay at 7.8. As soon as I use cal hypo though the ph will continue to climb. Yes, even after the acidic process of the chlorine being used up. I do have to use acid about every other day to keep ph in check while using cal hypo. Will it just be a never ending battle of using baking soda for low TA and acid for high ph?  With the TA on the lower side, shouldn't the ph want to fall on its own? There is a waterfall that's on 12 hours a day 7 days a week (falls from about a foot high). Also there was new plaster put in about six months ago, I know that can raise ph too for a while. My other concern is the CSI, would TA even be a factor in that whether it was at 20 or 150 if the ph did not move?

Fc - 2ppm

Ph - 7.8 (goal - 7.5 to 7.6)

Ch - 230ppm (tap water has low Ch, that's the reason for using cal hypo.)

CYA - 40ppm

TA - 70

Temp - 75 F

 

Thank you,

Blake

 

[RDspaguy 627]

Always get your alkalinity around 100 before you even look at ph. Low alkalinity gives you an unstable ph, and a fly fart will change it. You are also seeing ph rise due to aeration from your waterfall. Cut it back to 12 hrs and see what you get.