The Artisun Technology AT-HC-12-80-01 Hydro Chiller is ideal for cooling hydroponic reservoir tanks. It can cool a 27 gallon tank by as much as 10F when operated correctly. Insulated tanks can be cooled to lower temperatures. Larger tanks can be cooled using multiple Hydro Chillers. Cooler water temperatures allow higher Oxygenation levels which drive growth.The Hydro Chiller uses a large cooling bar and thermoelectric technology to chill water in the reservoir. The cooling bar is inserted through a 1-7/8” hole drilled in the side wall of the reservoir and is sealed using a silicone washer and large bulkhead nut.