Constant High PH

[bdearen]

Hello,

I have a 20k gallon in ground gunite pool from 2006. I purchased the house about 8 months ago and drained the pool as the CYA was so high I couldn't even chart it. Everything has been going great except I am constantly battling high PH. I have tried to dose with 1 quart of acid every other day and it drops it down for a few days but then again about a week later I am right back up on PH. I have also tried larger doses with the same result. Is there anything I can do that I am missing? I am using Hasa liquid Chlorine and Hasa 31.45% acid.

• FC 2.5
• PH 8.0
• TA 140
• CH 220
• CYA 20
• Water Temp 78 degrees
• 2HP pump that I run for 5 hours per day

 

[PoolGate]

Do you have any water features? How often are you in the pool? I think you are saying you manually chlorinate with liquid chlorine? A quart every other day is not a super lot. I use about a gallon/week in the swim season to keep my pH down.

 

[IceShadow]

What is the pH / TA of your fill water? Do you have an auto-filler? Do you know how much water you're adding due to evaporation?

 

[bdearen]

Do you have any water features? How often are you in the pool? I think you are saying you manually chlorinate with liquid chlorine? A quart every other day is not a super lot. I use about a gallon/week in the swim season to keep my pH down.

I have a spillway that I am turning on for 30 minutes per day to chlorinate the spa. We haven't used the pool much yet but with summer coming we will probably use it 1-2x/week. Good to know, so it's normal to use this amount.

 

[bdearen]

What is the pH / TA of your fill water? Do you have an auto-filler? Do you know how much water you're adding due to evaporation?

The PH of my fill water is 7.6 and TA is 140. I am manually filling the pool about 2" 1x/week.

 

[IceShadow]

Your high TA is likely what is causing the pH rise. Your pool TA is about the same as your fill water. I suspect you are reducing it as you bring the pH down, but then refilling the evaporated water is bringing the TA back up.

Do you have a solar cover? It would help slow evaporation, and that in turn would reduce the TA rise from evaporation -> filling. Otherwise, you can try to force TA down by aerating to raise pH, then acid to lower TA and pH together, but that just means you're putting a bunch of acid in in succession instead of over time.