Good Point..I have read that people poke holes in paper plates and put them over the plant so that the heat does not transfer to the pellets and then to the water. I Plan on doing that and covering the plates in foil tape. I also just got off ebay a Digital Water Thermometer to monitor the water temp from what I have read I want to keep the water 68-70 for ideal conditions. Dont forget about the 80mm Fan at the top right above the lights that should suck allot of heat out that those lights produce.