Chillers

Chillers are basically air conditioners for your aquarium water

It's a small unit that cools the water circulated through it from your tank.

The water goes into a chamber containing an evaporative coil. The water temperature is lowered as it's exposed to coil which contains a high pressure of gas which transfers the heat from the water to the gas in the coil.

The coil is corrosion proof and there's some other differences from a regular air conditioner. Chillers are a great way to maintain a constant temperature within your aquarium, which is very important for maintaing healthy corals. 74- 78 F is probably the optimum temperature for most reef tanks.

On larger systems, it's almost mandatory to get a chiller because it's very difficult with lots of lights and pumps to keep the temperature down.

Home Air Conditioners

Some people just turn up the airconditioning in their house if their tank is not too large, and this works fine. In some cases, you may not need a chiller if you can run your house air conditioner to offset the temperature increase. But if you are cooling your entire house just to keep your tank temps down, it might be cheaper to try something else.

Fans

Or you can also use a fan that blows over the surface of the water which provides evaporative cooling and can bring down the temperature several degrees which which may be just enough to keep you with a net safe range. of about 72 to 82 tanks. We don't recommend higher than 82 F as often times SPS stony corals can start bleaching. Especially if the current is low or still.

Bleaching is an effect that's often happening in nature. Many areas are getting much higher temperatures as global warming increases, and sometimes the water currents slow down and then suddenly they get massive bleaching over many many acres of corals. It is terribly heartbreaking to see that situation in nature or in your tank.

Sizing your Chiller

So to avoid that happening to your system, you can get a chiller. They are not cheap. They cost hundreds of dollars depending on the size. You want to make sure you get one that is NOT undersized. Follow the manufacturers recommendations regarding sizing.

Many people try to make their own chillers, and we've even try to make her own chillers using a water tube going through a refrigerator. We also dug a hole in the ground and sent a plastic tube in the grou, which is cooler and acts as a heat sink. But after all of this we found that none of them really worked efficiently. Basically you just don't get enough pull down of the temperature over time. The refrigerator coils werent powerful enough to draw down the temperature of the water circulating through it. And the ground warmed up around the coil and the heat transfer was minimal.

But hey, have fun and play with them yourself. Maybe you can be the one to make a refrigerator chiller that really works. And if you get a design that truly works let us know. But for efficiency and for the best use of electricity, I think chillers are probably on the way to go.

Beware of inferior chillers

Beware of some chiller distributors or manufacturers selling inferior products. Check the forums and see which ones are recommended impartially. We had a very bad experience with a distributor who wouldn't back up the chillers he was importing from China which has a serious design flaw. The flaw caused the coils to leak during shipping and he wouldn't stand behind his product.

So buyer beware.