does metal in the res raise ph? i have some stainless steel in mine to keep my airstones from touching the side of the res and vibrating. the sound is annoyingNo it shouldn't. Do you have any metal in your res?
This is the case with all my blue lab meters and many other brandsI have a meter that gives false readings if I stick it where the bubbles are,try takeing a glass off nutes out of your res and test it,if you still have the problem you got something going on in your res