i need a way to cool my water, its only a 5.5 gallon but when i leave for work its at about 77 and when i get home it gets up to 84, and im not around all day to add ice cubes or anything like that. any ideas of what i could do? its just so warm in my house that its raising the temp in my tank. i leave a window open and have a fan in the room with my tank.