@Rdub, have you ever checked the pH in the float area and compared it to what your rez pH is?
I was shocked at the difference once but I was also dealing with a switch to dry plant food and all that..
All I know is I couldn't keep the pH from fluctuating in my rez when I ran air stones in it, so I took them out.
The woman at the grow shop said to run them the guy said you don't need them.
edit: I also said I don't need the air domes do I?
Can't I just run air stones inside the bottoms and save $$$