For those of you interested in keeping a cooler tank without using a chiller will be interested in systems that use cooling towers and fans to remove heat from the water column and to increase evaporation (a big deal for some tanks with heavy
stony coral pops). The concept is to use a pump that is thermostatically controlled to come on when the temp reaches the predetermined maximum heat. This pump then pumps water to the top of a slatted or corregated column that has a large surface area due to the slatting/corregation. TYhe water is then trickled or sprayed over the surfaces of the internal surfaces of the tower, where they trickle down the interior walls and collect in the sump to be returned to the tank. An electric fan is arrainged so that it pulls air from the bottom to the top of the column, increasing evaporation due to increased surface area, which cools the temperature of the water. The effectiveness of this method is determined by the height and surface area of the cooling tower, and the speed of the air moving through it, but it is very effective in cooling water temps to acceptable levels. Should be a number of sources for information and plans on the internet.
Hope this helps,
