Ice packs to chill tank in summer?

[reefmandan]

I don't know why people bother with frozen water. Water has one of the highest heat capacities of anything on this planet, that is, the ability to absorb or give off energy without greatly affecting the temperature.

Evaporative cooling (i.e. using a fan) works wonders, and is far more economical than using frozen water. Placing a fan on top of your tank or in your sump is usually enough to deal with any issues, and when combined with a controller works wonderfully.