If you dont have a glass hood and you have decent aeration, try opening a window. I know it sounds totally random, but your house might have too high co2
making your pH drop. It was/is my problem.
Also, before you try a PWC
, check your alkalinity. If its low, you need to raise it to proper levels. Depending on the salt you have, I know a few salt mixes out there have a base value of something like 2.8 dkH
which is way low and that'll make your pH low. Point being: all the PWCs in the world wont help if each one brings your dkH
down that low.