I know that if FC gets too high then the PH numbers will be off. Question is are PH numbers the same at FC levels of 4, 6, 8 (all in range of my CYA of 50) I am seeing some PH bounce around over the last week or so from 7.4 to 7.7-7.8(not quite the color of 7.8 but not 7.6). I didn't record the FC when I did the testing so the FC could be between 4-8 which is where I try to keep it. I know my TA is low but it was recommended here to leave it be unless you are getting PH bounce. I wish there was a drop test for PH like all the other test we do , trying to look at a color is pretty subjective to lighting.