Yesterday I got my 250w MH lights, so good so far, in the first 4 hours of use the temp in my tank only went up 1 degree, not bad considering the temp in the house went up from 71 to 84, NO! I can't use AC, my wife is from the Philippines and 84 to her is very comfortable, by end of the day the temp in my tank was 83, this will not do, today its suppose to be 90. Lights on this morning, still 82 in the tank, this will not do, I may not even turn on the MH lights today, perhaps I may need to consider a chiller, I know nothing at all about this piece of equipment, the IT WORKS! Is my budget level. And don't tell me Odyssea makes a Chiller, hahaha!!