Homemade Aquarium Chillers

Types

• There are two types of commercial aquarium chillers: drop in chillers and inline water chillers. Drop in water chillers consist of coils placed in a sump, and they don't require plumbing. Inline water chillers have internal cooling coils. In an inline water chiller, water is pumped out of the aquarium and into and through the chiller, then back into the aquarium. Inline water chillers are more practical to make as a do-it-yourself project, and they can be placed away from the aquarium or hidden.

Traditional Chillers

• There are a couple of different ways to make a traditional homemade aquarium chiller. One way begins with a small (dorm) refrigerator, and the other way begins with a window air conditioning unit.

  To use a dorm refrigerator, drill two access holes through the top of the unit large enough for PVC pipe. The PVC pipe will direct water from the aquarium into and out of the chilling unit. You need two pieces of 1/2 inch thin-wall PVC pipe, each about four inches long. One piece of PVC pipe should fit through each access hole you drilled through the refrigerator. To affix the pipe to the refrigerator, use epoxy glue and then some silicone caulking to make a watertight seal. Then, you need between 50 and 100 feet of 3/8 inch hard plastic tubing and four PVC fittings for the cooling coil and the tubes leading to and from the refrigerator.

  Cut two pieces of tubing long enough to go from the refrigerator to the aquarium. Position the refrigerator as close as possible to the aquarium. If you have to run more than ten feet of tubing between the aquarium and the refrigerator, insulate the tubing to prevent the water traveling through it from being overly warmed by the room temperature.

  The rest of the tubing forms a coil that goes inside the main part of the refrigerator. Attach a PVC fitting to each end of the coil, then attach the fittings to the PVC pipes with epoxy and silicone. Then connect one piece of tubing to the aquarium pump and attach the other end to one of the PVC pipes using a PVC fitting and epoxy and silicone. Connect the final piece of tubing to the other PVC pipe in the same way and run it back to your aquarium. The pump will feed aquarium water into your refrigerated cooling system and pump the cooled water back into your aquarium, reducing the overall water temperature.

  You can make a similar aquarium chiller using a window air conditioner instead of a refrigerator to cool the water. Carefully take the air conditioning unit apart until you reveal the copper coils. Remove the aluminum fins using pliers. Clean the coils well with fine sandpaper and a degreaser. Then apply several thin coatings of epoxy resin to the coils. The most difficult part of this project is to then build a watertight acrylic box around the coils with entrance and exit holes. Water from the aquarium will be pumped into the box from the aquarium to be cooled and then leave the box through the exit hole to be returned to the aquarium. After the entrance and exit piping is inserted, the holes must be sealed tightly with waterproof caulking.

Other Methods

• If you're not ready to build a traditional inline aquarium chiller, there are simpler ways to cool the water in your aquarium. Evaporation cools water, so you can use either a small household fan or a computer fan directly above your aquarium water to create evaporation and therefore a cooling effect.

  You can also fill a large cooler with ice and ice water and pump aquarium water through tubing that passes through the cooler, which will cool the aquarium water. Caudata Culture notes that while this method is effective you will need to refill the cooler with ice water at least once per day, if not more frequently.

  If you have access to an office-style water cooler, you can apply the same principle and not have to refill the water so often. Run tubing into and out of the water cooler tank, using a pump to circulate the aquarium water through it.