My tank crashed this morning. Woke up at 8 am and looked at the tank and everything was dieing! I think most of the fish are dead, corals are not doing good at all. Did a 50% water change and more water is mixing right now. Now its 11:20am and everything is starting to get better once I did the water change an hour ago. That's good I had another tank running(8 gallon biocube) I put all my favorite stuff in there and that stuff is alive. The only things that were alive and well and weren't affected by the tank crashing were the leathers, all the gorgonians, and all the shrimp. I have no idea why the tank crashed, yesterday the tank looked amazing, the best its even been. Everything was open, happy, and doing very well. The only think I did on Saturday was clean the back chamber of all the fish poo, did a big water change(like 10-13 gallons or so), and changed out my GFO like I have done every month for several months. Threw away the 40 grams of old GFO and added 25 grams of new GFO. Can't think of anything that would do this unless the power went out on the tank for some reason.... Right now, I'm looking into making an automated water change system and hook it up to a controller and a battery back up system for the powerheads. So, if the params go out of whack the automated water change system turns on or if the power goes out, the powerheads will turn on.