Aerating your water to increase your pH


Well-known member
May 28, 2010
I've read here that pointing the returns upward toward the water surface will aerate the pool and help increase pH. My question has to do with how much movement on the surface of the water is sufficient to aerate the water? Does water actually have to 'break' the surface or will even subtle / soft ripples on the surface of the water cause enough aeration to affect pH levels?

Reason I ask is this...

Recently my pH has been holding quite steady around 7.5 and my TA around 90. I hadn't been testing my water for a few days as I waited for my replacement/refill reagents to arrive. During that time, my water level has dropped about an inch or so do to evaporation and as a result, the 'ripples' on the surface of the water became more pronounced due to the surface dropping closer to the returns. Today I tested my water and the pH shot up to 8.0 which surprised me a little b/c there hasn't been any unusual amount of rain or anything else that I thought would affect the pH levels so much in only a few days. Then I saw another thread just now recommending to aim the returns up to raise the pH and it got me thinking... if the water level lowering due to evaporation is what caused my pH to go up?


TFP Expert
LifeTime Supporter
Feb 23, 2008
Denton, TX
Anything that creates bubbles in the water will raise your pH. Bubbles from swimming and splashing, returns breaking the surface, waterfalls, etc. will cause the pH to rise.


TFP Expert
LifeTime Supporter
Mar 29, 2007
Coastalish 'down easter'
Well, it could be more 'active' aeration - as I understand it, the more you break the surface, the more aeration occurs. Another possibility is the fill water you used, did you test it?

chem geek

TFP Expert
LifeTime Supporter
Mar 28, 2007
San Rafael, CA USA
It all comes down to the amount of surface area you create between the air and the water. Creating ripples creates more surface area and also mixes TA-rich water as close to the surface as possible so yes, that counts towards increased aeration. If you have the water flow break the surface to create water globs, then that's more surface and even faster aeration. If you have water droplets form as with a fountain, that's even more. If you have air injected into the water, especially if very small bubbles are formed, then that's more aeration. Waterfalls and spillovers also produce a lot of aeration. Rain can produce aeration, but pH affects are more complicated in that case. Lots of kids regularly splashing, lots of people swimming, etc... you get the idea.
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