This tank is fairly new but the rock came from another one of my tanks that was running for over 3 years.. I don't think it's parameters I run a triton system and all of my other corals are doing great. My parameters are nearly perfect. This tank is 36x20x20, 2 kessil A360we, 2 mp10, 1 gyre which I only turn on a few times a week to kick up detritus, a chaeto reactor, skimmer, phosphate and carbon reactor....