Many years ago when I just started I used to use ice. What I did was to remove a few liters of tank water, and then made half-liter sized "ice cubes" by freezing the tank water in small jugs. I then placed the ice in the sump when temperatures reached dangerous levels (+29°C), and it worked quite well - only problem was, somebody had to be at home to do this, as the tank usually reached it's highest temperature during the afternoons while I was still at work... enter long suffering wife and kidsAm i the only one though using ice?
a chiller is one of the best investments one can make for you tank.... it takes a lot of worry out of keeping marines