Saltwater Aquarium Chiller Guide

Chiller Guide For Saltwater Aquariums 


When it comes to aquarium equipment, there are a variety of things that you may need depending on the types of fish and marine life that you have in it. Regardless of marine life, however, one of the most important things you can do for any saltwater environment is to keep it at a stable temperature. I always say that stability is the key to a successful aquarium. In most marine tanks, you will want a temperature between 76 and 80 F, and you will need a water heater to keep this temperature from dropping. But what about when the opposite is true? Is there ever a time that you will need an aquarium chiller instead?


What is a chiller?


If an aquarium heater heats the aquarium, then an aquarium chiller does just the opposite –it chills the water and keeps it cool for inhabitants that need cooler temperatures. Basically, they are like mini-refrigerators which are equipped with in-line filtration systems.

To make it easy for you to keep track of the temperature in your aquarium, most chillers are equipped with thermostat control. You can choose between single-stage controllers or dual-stage controls, wherein a single-stage controller only controls the chiller, but a dual-stage controller controls a chiller and a heater.

Recommended aquarium chillers:




Why Would you need an Aquarium Chiller?


Some fish need cooler water and higher dissolved oxygen than the water can provide on its own. In such cases, maintaining a cool environment will be essential for the survival of your fish. The warmer your home or climate is, the more likely you will need a chiller for certain types of cool water fish.


When do you need a Water Chiller?


You don’t always need a water chiller for cold-water fish. If you live in a cool environment, it might not even be necessary. But as a general rule of thumb, you need a water chiller anytime the room temperature is higher than the desired water temperature. Situations like this may arise when you wish to keep cold water species in an indoor aquarium, when you live in an area that is subject to sudden spikes in heat, when you live in a warm location of the world, or when you’ve installed equipment like pumps and lights that give off too much heat for your aquarium needs.

It’s also important to note that water chillers aren’t only necessary for species from arctic parts of the world. Rather, contrary to popular belief, some subtropical species can also benefit from a chiller during intense heat spells.

Anytime your aquarium is in a location where the water needs to be cooled to the proper temperature, you need a chiller.


 Marine Depot Aquarium Supplies

Do you need a water chiller? Things to consider:


  • What is the summer weather like where you live?
    • If you live in an area where your hottest months are relatively cool, you might not need a water chiller for your aquarium (unless you are heating your home). But if you live in areas that are subject to intense heat fluctuations and spikes, a chiller might be a good idea to keep your fish healthy.
  • Do you have Air Conditioning?
    • If you live in a hotter area but have AC in your home, you might not need to invest in a chiller. Again, as long as your room temperature is not over that of your aquarium needs, you can probably eliminate the need for a water chiller.
  • Aquarium location
    • When trying to decide whether or not you need a chiller, don’t just focus on the temperature of your home, focus on the temperature of the location where your aquarium is placed. If it’s in a well-insulated, cool basement, you might not need a chiller. But if your aquarium is in a stuffy office, you might need help keeping it cooler. Also, consider placement in the sun. If your aquarium is in direct sunlight, it may need to be kept cooler during the day.
  • Lights and pumps
    • Though many people don’t think about it, lights and pumps are huge influencers of water temperature. This is especially true for tanks that have metal halide lamps, which tend to run much hotter than some other types of bulbs. Sometimes, things like these can send your water over the desired temperature. In such a case, a chiller will be necessary.


Before you run out and buy a water chiller to cool your aquarium, try running a fan over the top of the tank or sump. Sometimes this is all you need to cool your aquarium by a few degrees. Just keep in mind that if you use this method, your water will evaporate quicker. In such cases, regular (usually daily) water top offs will be necessary.


Are there different types of water chillers?


Yes. Water chillers typically fall into one of two categories: drop-in chillers and in-line water chillers. A drop-in chiller consists of coils placed within a sump is placed in the aquarium and does not require any plumbing for setup. An inline water chiller, on the other hand, consists of internal cooling coils. Inline chillers are typically placed away from the aquarium, and the water pumps out of the aquarium, cools in the chiller, and then is pumped back into the aquarium.


How to set up a Water Chiller for Nano Tanks:


In order to install a Nano Chiller you will need:

  • A chiller
  • A feed pump
  • An installation kit
  • ½ inch hose clamps
  • And a Controller


If you have the option, insert a feed pump into the reservoir of your tank. If this is not an option, insert it into the main tank. Use a hose clamp to attach the U-tube to the pump and place it in the reservoir (or tank). Next, run your tubing from the pump to the inlet of the chiller using parts from your installation kit. Then, run tubing from the chiller outlet to the back of the tank and attach it with an S-tube.


Things to consider when buying a Water Chiller


It should come as no surprise that water chillers are not cheap investments. As such, you want to make sure that you are investing in a good unit that isn’t going to die on you in a few months. When picking out a chiller, you should consider:

  • The cost of the chiller
    • You don’t want to spend a fortune, but remember, you get what you pay for. Spend the extra money to invest in a high-quality chiller that you won’t need to replace for years to come.
  • Energy consumption
    • Chillers can consume a great deal of energy, which can raise the cost of your hydro bill. When choosing a chiller, check out the amount of energy that it consumes. Certain chillers are built to preserve energy, while others will just eat it.
  • Noise level
    • Some chillers can be extremely noisy. If your aquarium is in a location where this could be a concern, consider looking for a less, noisy unit.
  • Aquarium size
    • Obviously, when you buy a chiller, you want it to be big enough for your tank. Check your tank requirements beforehand to ensure that your chiller is large enough to do its job properly.


How to Create a DIY Aquarium Chiller:


Things you will need:

  • A hand drill
  • A drill bit (1/2 inch or 5/16)
  • Scissors
  • Screwdrivers
  • A small refrigerator with a freezer section
  • 1 foot of PVC pipe (1/2 inch) and fittings
  • Epoxy glue
  • Fifty to One hundred feet of hard plastic tubing (3/8 inch)
  • Temperature probe


Step 1: Within your refrigerator, there will be a box that isolates the freezer section. Remove this (if possible) but leave the temp probe.

Step 2: On the top, drill holes that are large enough for your plastic tubing

Step 3: Prepare two pieces of PVC piping, approximately 4” in length, and insert them into the holes

Step 4: Use your epoxy glue to reinforce the stability of the pipes. Seal very well with silicone.

Step 5: Run your 3/8” tubing from the pump to the chiller, and then from the chiller to the aquarium or sump. Connect them using your glue.



In conclusion, if you have fish that require water temperatures cooler than your aquarium is able to provide, you may need a chiller to help keep your water cool. With that being said, water chillers can be very expensive, so you might want to try a fan or a DIY option beforehand. If you do decide to buy a chiller, make a good investment and don’t cheap out.  Spend the extra money to make sure you a getting a high-quality chiller that will work.


Thanks for reading!