how hot is too hot?

so as the temp outside climbs so does the temp in my tank. the last few days it's been lingering around 83 degrees and sometimes even above. nothing seems at all bothered by the temp, all the corals my fish, inverts and nems have been acting totally normal (except the midas blenny going carpet surfing). i fear that the corals might not want to open up in the heat but they are opening fully. i try adding ice in bags to the sump but it melts so fast and hardly makes a dent on the temperature. i cannot afford a chiller. i guess that i'll have to raise my lights, they are very close to the top of the tank, only about 6 or so inches off the top (2x250w HQI with 4x54w T5's). i have no idea how i'll do this tho as i can't hang them... i already have a fan running across the top of the tank so i can't really think of any other options - anyone have any ideas?

yes jupiter jumped :cry: and no i don't add the ice directly to the sump i put it in a big zip lock bag - tho i admit my first thought was just to chuck it in fortunately i realized that mistake before it happened! hmm maybe a fan on the sump could help a bit...