cooling tank

becareful of the icepacks splitting! ro water is safest in case of leaks. Cooling air is going to be cheapest try a fan between the lights and the water and another over the sump run them timed with the lights. Also what other things are adding heat to the tank like subnersible pumps,power heads and such maybe adding a closed loop or get all external pumps would help offset the heat exchange. i have also cleaned up plumbing ( less 90's and such) and gotten better flow and lower temps

 

I've had a 75G with 2X250W MH and 2X110 VHOs for 3 years and never needed a chiller or ice bags. Just a few fans. I use 1 in the winter and 2 in the summer. It has gotten up to 36 C outside and have been able to keep the temp down the hole time

J