How do water features affect PH and TA?

[NtxMelanie]

I have a small Gunite pool (~4400 g) and a large spa (~1200 g) attached that flows into the pool. The pool and the spa both have large rock waterfalls, so when they are turned on, there’s ALOT or aeration. How does that affect my pH and/or TA levels? Right now my TA is 85 and my pH is 7.5 after adding a cup of 15% muriatic acid this morning.

pic of one of the waterfalls for reference, spa is 10 ft diameter.

 

[mknauss]

Aeration drives up pH by liberating CO2. TA is lowered when you add acid to lower the pH.

Can you run the system without running the waterfall?

PH TA Relationship - Further Reading

www.troublefreepool.com

 

[NtxMelanie]

Aeration drives up pH by liberating CO2. TA is lowered when you add acid to lower the pH.

Can you run the system without running the waterfall?

PH TA Relationship - Further Reading

www.troublefreepool.com

Yes, it runs most of the time without the waterfalls but always has the fall into the pool from the spa (as long as the pump is running). I just noticed the ph go way up after we swam and had waterfalls on yesterday for a few hours, so added acid and that helped. Does that mean I’ll likely need to add acid after every big swim? If so I better stock up

ETA: also is there a way to raise TA but not PH?

 

[mknauss]

Running the water fall will drive up pH.

How are you chlorinating? If tablets and using that Ozone thing, you will have to add baking soda often also. You will be on the hamster wheel of pH and TA. Not a good place to be.

 

[TexEdmond]

GORGEOUS!!!!

also is there a way to raise TA but not PH?

I believe a CO2 injection system might help keep your pH down while adding TA, but help us understand why you'd want that? Most of the time there's no reason to raise TA if it's at 85-90 already. Higher TA means you'll have to add MORE acid to the pool to keep your pH at the number you want. The simple answer to your question is, "no, because alkalinity is the main factor in the pool's water that causes pH to rise." Is there something you're seeing in your pool's chemistry that recommends raising alkalinity?

It's a good idea to test your fill water to know what you're changing in the pool's chemistry by replacing splashed / evaporated water. Well water especially, but also sometimes municipal water sources have enough alkalinity that you'll always be adding TA to the pool.