I seem to have an issue with my Nuvo 40 where the acropora slowly turn brown over the span of a few weeks. It's being lit by a Radion G5 Blue with AB+, at about 60% intensity. PE is good, just no color
Alkalinity: 11.5
Calcium: 450
Mag: 1500
Nitrates: 5-12ppm
Phos: .05-.09
ICP tests also...