Sorry if I am repeating myself, but just want to pass on some info that may save someone from the disaster that happened to me. My tank has been set up for 15 yrs now. I guess complacency set in and I had no problems with the tank at all. Corals flourishing, fish doing great..all was fine. I have a homemade water top off device, so I didn't really pay much attention to the tank.
But...about 3 yrs ago on a hot summer day I looked at my tank and saw not clear water, but milk. Evidently I had 2 major malfunctions. Don't know which happened 1st, but it doesn't really matter. My heater was stuck ON and the fans in my homemade light canopy both were turning around 1 rpm.The combination of hot weather, a heater being on and metal halides burning caused my water temp to hit about 95.
Needless to say, I lost virtually everying in my tank including my desire to keep up with any maintainance. I only cleaned up the mess and that was it. My tank ran for about 3 years with nothing being done to it because I lost my desire.
Well I finally got the urge to get it cleaned up again and now all is fine and I have that enthusiam back.
So, after all that rambling what I want to say is this. Take a few minutes each day. Check everything out. Be sure things are running like they should. You won't be sorry. I learned the hard way.