Yeah, I do have macro in the refugium section mostly for the purpose of nutrient reduction. However, I do run the fuge lights overnight so yes it affects PH. My running PH average is 8.38 and the min is 8.3. I've had a couple odd spikes that raised the max to 8.49. Probably about time to recalibrate the probe or cut the night light cycle. Other than that, never done anything to raise or lower PH. Also of note is the fact I run a CaRx.