Seems to be most of you hover in the 10% area. I have a heavy fish load in my SPS tank and with live rock in both sump and 150 display and 35 gallon sump/refugium, I'm calculating I have approximately 160 gallons of water volume. I change out 25 gallons per week, which calculates to roughly 16%. My parameters are:
NO3: 2
PO4: undetectable
Calcium: 430
Alkalinity: 9 dKH
Mag: 1320
4 Vortech MP40's in Alternating reefcrest mode
Iwaki 30 return
Temp: 80 - 82
All kept stable with a calcium reactor
Lately, my sps are showing average polyp extension but growth appears to have halted. My lights have not changed and they are actually about halfway through their life cycle.
Am I disturbing too much when I do a larger than average water change? That's really how I should have phrased the question.