I draw my water and let it sit while using air stones before I water with it as it is too cool, especially in the Winter. I also feed my plants with tea so I've seen the differences in pH as the water sits. So I draw the water and a day or two before I need to feed I add the nutrients. A day or two later I will adjust the pH before I feed the plants.
Temperature does change the pH reading for electronic pH meters but they have compensation for that. Even at that, the worse case scenario would be .5 difference at 4.0 pH with a moderate temperature difference. At 7.0 the difference would be about .02, very little.
Shovelhandle Reviewed by Shovelhandle on . air pump lowers ph? ive been working on making the shift over to an rdwc set up so first thing i made is a little bubbler for seedlings etc. just for shits and grins i ran it over nite(no plants yet) and i noticed the ph had dropped almost a full point and a half? can i expect that on a regular basis? not that its big deal i was just curious. save me some ph down if thats the case. Rating: 5