High pH and Low Total Alkalinity

[Mbdobson]

My current pool chemistry:
pH 8.2
TA 60
FC 2
CYA 40
CH 330
Water temp 82 degrees
Significant aeration due to spa waterfall
I only use liquid chlorine

I continue to add muriatic acid to bring the pH down but after a day at pH of 7.6-7.8 it climbs up to 8.0-8.2 despite a TA at the lowest limit of normal per your site. I have even turned my water features off for 6 hours each day to no avail. What is my next step to bring pH into normal range?

 

[mknauss]

Welcome to the forum!
How are you testing your pool water chemistry?
Do you have an automation system that you control your spa with?
I suggest you read ABC's of Pool Water Chemistry.

 

[Mbdobson]

I test with a TF-100 test kit. My pool is on an automated OmniLogic system the pump and spa waterfall run 18 hours a day. I should also mention the pool is equipped with an ozonator that runs continuously.

 

[mknauss]

Great.
The best thing you can do is disable the ozonator, as that is adding aeration which raises pH, and also program the spillover to run a couple times a day (morning and evening) for 20-30 minutes to chlorinate the spa. Then run it when you are there to enjoy it.

Those two items should dramatically reduce your aeration.

For now, I would add about 30 ppm TA worth of baking soda. Then lower pH to 7.6. Never reduce pH lower than 7.6.

 

[Mbdobson]

I think I should clarify. My pool pump when running draws from the pool but returns to the spa which then overflows via 3 small waterfalls to return water to pool. So if my pool pump is running the spa overflows are aerating.

 

[mknauss]

Correct. In your Omnilogic automation, schedule the Spillover (or Spillway) for 20-30 minutes twice a day. The rest of the time, the water will not go to the spa, just the pool.

Do you have a makeup line to run the spa when in Pool mode? If so, that will line will need to be shut off for the above to work.

 

[Mbdobson]

This pool plumbing may be over my head. On OmniLogic my spa spillway is a separate function which is always off except during freeze protect mode. Despite this fact if the pool pump is on water comes over the 3 spa spillways. The only way to keep water from coming over the spillways is to turn my pool pump completely off. I am definitely not a pool plumbing professional

 

[mknauss]

Take some pictures of your equipment pad. Return side especially. Look for a line that goes from the pool side of the return to the spa side. Will have a check valve on it, and hopefully a valve.

The programming is easy.

This is how you will get your pH under control. Or, you will be adding baking soda and acid. We call it the pH/TA hamster wheel.