DIY Aquarium Chiller made with a mini fridge.

[jossswonk]

I'm trying to get the water in my aquarium colder and I've been looking at some chillers but they're so expensive. I found some YouTube videos about how to make a chiller with a mini fridge so I want to see if anyone has had any success with that before I jump into a project or to see if I should just bite the bullet and buy a chiller.

 

[Archerfish]

Have you looked at other options besides those two? Perhaps closing the room shades and adding a small room A/C unit? Relocating the aquarium to another, cooler location? Evaporative cooling if you only need a few degrees of cooling works too. Perhaps keeping heat tolerant fish?

 

[GaryE]

I used to know people who made fridge chillers. Unfortunately, they were all older aquarists I lost touch with since I only knew them online. Whether the systems didn't work or age got their makers, I don't know. They were popular projects in a small circle of diehard DIY aquarists in the 90s.

They talked abut condensation on the glass of their tanks.

What kind of temperature range are you looking at, and how long does the heat get oppressive where you are? I've discussed keeping tanks cool here as I keep Aphyosemion killifish that like the very low 20c celsius. It's easier for me because I'm on the coast with more moderate temperatures to begin with though.

 

[Magnum Man]

I put a coil of hose in a mini fridge, many years ago my intended purpose at the time was for cool RO drinking water... it didn't work that well, but it was one of those thermo electric units, not a compressor type refrigeration unit... you could do the same, I just drilled 2 -3/8 inch holes through the side, ( research your drill sight 1st, so as not to hit anything vital in the refrigerator ) the coil size will be critical, both in diameter, and in the amount of loops... it may take several attempts to get the right amount of cooling, so I don't recommend sealing around the hose, until you are sure you have the right size coil loop... I'm not sure if they still make those "dorm room" thermo electric units anymore, but because of the cooling limits of those units, I'd recommend a small refrigerator, with a traditional compressor cooling...

 

[Uberhoust]

How far do you want to cool your water down? Are you planning on insulating the tank. When I was studying the biological department at my school used chilled aquariums for their native ocean tanks and they had constant condensation issues to the point they made drains for the condensed water just like air conditioners or heat pumps use now, and the tanks only had a front window.

Peltier cooling systems are still available (old style bar fridge), you can buy just the thermoelectric unit itself or a fridge built with this type of technology, but I would say the mini compressor types are more efficient. I just purchased a portable freezer unit (mini compressor) that can cool to -18 c, it could maintain this temp for a 1.1 cufoot volume using only 60 watts, I don't believe a peltier system could easily do this without some type of staged cooling systems, ie multiple peltier systems. That said the compressor style will be more noisy.

First step would be to determine how much cooling you are targeting. There are some rough calculators to determine BTUS based on size of tank and temperature drop desired here: https://www.fishlore.com/ConversionCalculator.htm. A more detailed site is here: https://www.hamzasreef.com/Contents/Calculators/HeaterChillerSizing.php (I used this site to determine size of heaters when I put tanks into a cooler room and the heaters I had couldn't keep up). Once you have this information then you might find out that your little bar fridge has no hope of cooling your tanks or that maybe you can get by with a smaller one.

The Alpicool C15 portable refrigerator I mentioned earlier has a simple box with a polyethylene top that would make modification to have water lines in it pretty easy. I haven't used it long enough to state whether it is reliable yet.

 

[jossswonk]

After all this info I think I'm just going to invest in a chiller. It will give me more peace of mind in the long run I think.