DIY aquarium chiller

How to make a homemade aquarium chiller

Equipment

• A hand drill
• A ½ inch or 5/16 inch drill bit
• Screwdrivers
• Knife or scissors for cutting tubing and pipes

Materials

• A small refrigerator with a freezer/ice cube tray section. A 1-1/2 cubic foot refrigerator is suitable.
• ½ inch thin-wall PVC pipe. You will need roughly 1 foot.
• Epoxy glue (5-minute)
• PVC fittings. It doesn’t matter if it is threaded or slip.
• 3/8 inch hard plastic tubing. You will need roughly 50-100 feet.
• Silicone sealant suitable for aquarium use.
• A pump/powerhead (powerful enough to pump water through the chiller fast enough)

Overview

Everything is placed in the plastic box inside the refrigerator housing.

The turquoise square on the sketch symbolizes the freezer compartment with a temperature probe attached to the inside wall of the cooling box.

Point 1: This is where the water will enter from the pump.
Point 2: The water is transported through the 3/8 inch coiled plastic tubing. (The more coils, the better the cooling effect.)
Point 3: This is where the chilled water leaves the chiller.

How to make a homemade aquarium chiller

• Ideally remove the box that isolates the freezer/ice cube tray section from the refrigerator. (In some models, this will unfortunately be virtually impossible.) Leave the temperature probe as it is.
• Drill access holes for plastic tubing on the top. (You can also drill them in the sides; the important thing is to choose access points that are practical for your particular set-up.)
• Prepare two pieces of PVC pipe; roughly 4 inches each.
• Insert the PVC pipes through the access holes.
• Reinforce the pipes with epoxy glue at the access holes.
• Seal with silicon. It is important to seal well.
• Glue or thread the PVC fittings onto the pipes and connect the pipes to the 3/8 inch tubing inside the box (coiling) and outside the box (running from the pump to the chiller and from the chiller to the aquarium/sump).

Important factors to think about

#1: The pump must be powerful enough to keep the water fast flowing; otherwise it might freeze to ice inside the chilling box.

#2: When the water runs back from the chiller to your aquarium it will be heated up again by room temperature. Using a long piece of plastic tubing between the chiller and the aquarium is therefore not a good idea. If you have to use a long tube, insulate it properly.

How to make a homemade EMERGENCY aquarium chiller

If you need a quick emergency remedy for your over-heated aquarium while putting a more durable construction together or waiting for a ready-made one to arrive, you can try this emergency chiller.

What you’ll need

• A small canister filter with the motor on top
• A bucket
• Plenty of ice

What you’ll do

• Fill the bucket with ice.
• Immerse the lower half of the canister filter in the ice.
• Use the filter as you would use a normal aquarium filter.
• Replace the ice continuously.

As mentioned above, this is just a quick emergency solution– not something that you can rely on in the long run. You have to monitor the temperature in the aquarium closely because this type of emergency aquarium chiller can easily cause dangerous fluctuations in water temperature. DO NOT unplug your heater.