DIY CHILLER...would this work?

"¢Dorm-sized refrigerator (1 to 1-1/2 cubic feet).
"¢50 to 100 feet of 3/8 inch hard plastic tubing (depending, vinyl isn't as good a choice here).
"¢PVC fittings (90 degree elbows or straight connects, threaded or slip).
"¢Aquarium safe Silicone sealant.
"¢1/2 inch thin-wall PVC pipe (about 1 foot for the "thru-the-box" connections).
"¢Hand drill and 1/2 inch drill bit (or 5/16 inch if you prefer).
"¢Screwdrivers to fit the various hardware of the particular fridge you own.
"¢Rio 2500 or similar pump/powerhead to push the water through the chiller

If possible, remove the metal box that isolates the ice cube tray/freezer section, but leave the temp probe alone. This will give a better overall temperature control within the cooling box.
The more coils, the better the "pull-down" effect and the more efficient the unit operates. Depending on the brand/model that you are using, you may encounter insulation between the housing and the inner box when drilling your input/output holes. There is no need to seal the door.
"¢Drill your access holes in the top or sides, it really doesn't matter.
"¢Cut 2 pieces of the PVC pipe about 4 inches each.
"¢Insert through the holes drilled and seal VERY WELL with the silicone.
"¢You may want to reinforce these pipes with a little Devcon 5 minute epoxy
"¢Glue or thread your fittings onto these 2 access pipes.
prior to sealing them with the silicone. Keeps 'em from sliding back and forth and breaking the cured silicone seal should you want to move the fridge down the road.

Remember that the more coils inside the box, the better your cooling effect.
Another point to consider, the farther the run of plastic tubing from your sump to the chiller and back, the greater the line loss due to ambient room temperature. Sit the chiller as CLOSE to the sump or aquarium cabinet as possible. You could use pipe insulation wrapped around the tubingrun(s), but this is rather unsightly and not really necessary unless living in a very hot/humid environment.

Operation is straight-forward. Remember to keep the flow fast enough to prevent freezing of the coils inside the box. If equipped with a thermostat, your fridge/chiller will be easier to control. Some models only allow you to set the main box temperature, not the freezer compartment. That's another reason why I removed the aluminum ice cube divider and tray. The probe that is attached to the wall of the freezer area will now monitor the entire cavity. Try to use opaque tubing to eliminate algae growth from the sump to the unit and back. You will probably get the black, smudged variety, not the bright green that we see in and around the lighting canopy. I used the milky-white, semi-transparent variety of hard, plastic tubing and experienced this build-up after 6 months or so.
Thank you for the link, read the whole thing ........ If it sounds to good to be true it's because it is to good to be true... What about what it said about water evaporation? Would small clip on fans work?


New member
jolliebrowngiant, I have basically the same setup, small frige with about a 100 feet of 3/8" hard plastic line sitting in a tub of water. For the pump I use a pondmaster 550 that I had laying around. 25 feet of 3/8" line goes from my aquarium to the pump, then 125' of 3/8" line for the return (100 of this in the cold water). The pump is plugged into my Reefkeeper set at 77.5 degrees. WORKS GREAT!! Only ever has to run about 3 minutes.

Here is a photo of the inside setup.
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New member
heck with the dorm fridge , just spring for a kegerator , wrap the lines around the barrel ..... now your doing 2 things , keeping the tank cool , and you :)


Far From Average
I have a heat exchanger like this set up on my tank it does assist the chiller quite well I am pretty sure it has reduced my chillers working cycles by half, I also had the same heat exchanger but without the fridge just a fresh water line from a spot in my house plumbing close to the well were the water stays cold around 62 degrees you just open the fresh water valve until the dripping water coming out the end is slightly cooler than the target temp (or dt temp) although I have the fridge on in my heat exchanger I think the fresh water drip does most of the work.


New member
You have proven that this does work on a smaller tank...thank you for the info and the pics...
Should clarify, might work, but ONLY on smaller tanks and in houses that don't need too far a pull-down in degrees. If you are in a warm/hot climate and don't have A/C going, you will still struggle. The tiny dorm fridge compressor isn't nearly powerful enough to handle anything bigger than a 20-30g setup at best, imo.

There have been scores of threads exactly like this over the years. Do some searches, read, and find out what the limits and success rate is.
So true Ghosty....lots of things to factor in...and I live in the High Desert. Very hot and very cold. So I am trying to get as many ideas as I can b 4 I go out and start a new project... So many great ideas and great feed back....good to bounce ideas off each other.