I feel like this is a silly question considering how many years I've been at this but I've run into this situation before and I've never asked. I try keep my nitrates at 10 or above and my phosphate no higher than .05 but also not to low... My reason for this is that I run an algae reactor and the cheato that stops growing if my nutrients get to low and also these parameters seem to keep my sps, lps, and softies happy... It's a sweet spot for my mixed reef tank... My problem is that when I'm at these numbers and my tank is looking good water changes will drop my no3 and po4 to low and I will sometimes get bleaching or cyano. I feed twice to three times a day, my tank is moderately stocked, and a dose b-ionic 2 part. I run a skimmer, algae reactor, and I have a marine pure block in my sump... Other than that I do 20% water changes every two weeks. So my question is when all you're parameters are perfect do you skip a water change and wait for nutrients to come up a bit or is it better to do the water change and start dosing nitrate ?