biggest issue at the moment is the heat wave we are having in the u k , I have been keeping marines for 48 years and have never had a problem with my tank being to hot, but over the last few weeks and temps of 30 to 33 degrees (101 F) even with fans blowing ice packs at the tank ,my water is 85 to 88 F, and all my corals are bleaching . i think buy the end of this week i will have a tankfull of dead motipora