I talked to Sone a bit last night on chat about this. I was wondering if I am experiencing rtn/stn or bleaching? Sounded like Sone was thinking bleaching but we didn't actually finish our talk before everyone butted in. /site/DesktopModules/NTForums/themes/_default/emoticons/shocked.gif jk Many SPS and LPS corals look very good like my rose Mille, purple bonsai and yellow mille (among others). However others are turning white slowly, no tissue falling away just turning white and dyeing. Mostly from the bottom but some from the center. So I am thinking bleaching. This is happening slowly but is noticeable with my purple digitata, powder blue stag and a few other unknown montiporas. But again my red and green cap, purple stag, purple tip mille and others are doing well. I am also noticing this tonight with a coral I got from Ryan at the swap he called "similar to Tyree ultimate" which is a real bummer. But the Subulata I got from him seems to be doing well. So anyway I need to double check my params(tomorrow night). But so far .... 0 Amm - 0 Nitrite - 7 Nitrate - 480 CA - 3.5 ALK (meq/l) - PH 7.9 - 8.1 - temp 77.7 - 79 So if this is bleaching (any other ideas) what are the main causes I need to look out for? Sone mentioned GFO which I am running. What about too close to the lights? Some of these corals are about 6 inches from 250W 15K XM's. I haven't tested Mg in a while? I dose just Kalk replacing all top off. Oh and salinity @ 1.026.