High cage temps

[Serpens]

I'm having some problems with my cage overheating. I live in an apartment, and I try desperately to keep the temp around 80, but it's getting really hard during the hot spells. I'm using a 40 gallon aquarium right now to house my corn, with two different heat lamps that I turn on and off to make different combos for the hot spot. The problem is the general temp in the apartment is raising the temp in the cool end of the tank to levels that I really don't like (82+). I was thinking of getting a couple cool packs from the drug store and then rotating them into the cage to try to drop the temp, but wanted some input first. Should I go with the ice packs, or is there another way to reduce the temp? My corn seems ok so far, but I just don't like to push the boundaries. Any input would be appreciated.

Thanks in advance,
Serpens