JBJ Chiller Calculator

gallons
gallons
°F
°F
watts
watts
watts

Please keep in mind the factors below for optimum chiller performance:

  • Ambient temperatures exceeding 95 degrees Fahrenheit
  • Excessive heat load from equipment
  • Placing chiller in a well-ventilated area
  • Keeping Condenser Grill clean
  • Providing minium flow requirements

Water temperature is important to aquatic life and especially to marine life in a reef aquarium. Fish and invertebrates are poikilotherms or “cold-blooded.” This means their body temperature and metabolic rate is controlled by the environment. In our case it’s the aquarium water temperature that determines the metabolic rate of captive marine fish, SPS and LPS corals, shrimp and even the invisible microbes that biologically purify the water and recycle nutrients. If the reef aquarium water becomes too hot, aquarium life becomes stressed. Stress works against the immune system, putting reef fish and invertebrates at risk to disease problems. When corals are stressed and in a weakened state, they can’t easily resist disease problems or heal from otherwise harmless tissue wounds. No reefkeeper wants to deal with sick fish. Temperature stress also negatively affect fish too, making them less resistant to ever-present disease organisms like parasites and bacterial pathogens. Even a tiny skin abrasion creates an opportunity for disease organisms to attack the tissue. Healthy fish heal quickly. Stressed fish often come down with secondary diseases that makes things even worse. In nature reef environments have very stable water temperatures. We want to duplicate this temperature stability in our own reef aquariums. But what causes adverse temperature fluctuations for reef tanks?

In most instances overheating is the main temperature problem in reef aquariums. Every electrical device in contact with aquarium water will transfer heat to it. The primary heat transfer comes from water pumps and lighting fixtures. Flow and skimmer water pumps add heat too. Even the tiny powerhead inside a nano AIO aquarium’s filter contributes heat to the tank. All aquarium lights add heat to the water. Fluorescent and metal halide light bulbs are notorious heat sources. LED light fixtures run much cooler but still radiate heat. Sometimes aquarium overheating is caused by hot weather or poor HVAC control. It isn’t always practical to rely on room air conditioning to reduce aquarium water temperature. Fortunately, aquarium chillers are available for just about any size aquarium.

Aquarium chillers cool the aquarium by removing heat from the water and transferring it someplace else. Despite its name, chillers don’t add "cold" to the tank. “Cold” can’t be transferred into the water. Water is cooled by extracting heat, which lowers the temperature. You’ll notice the same principle with refrigerators. Heat is removed from the air inside the fridge and freezer. It is transferred to the air behind the unit. That’s also why you feel hot air blowing out from the rear of an air conditioner. As water flows past the cool side of the chiller, heat from the aquarium water is transferred to the refrigerant gas. This heat energy is released from the “hot side” of the chiller and into the air. Proper sizing of the chiller is important! If the chiller is too small, it won’t be able to keep the tank cool and will waste electric. Too large and the chiller will “short cycle”, never running long enough to efficiently maintain the temperature. But don’t worry, we’ve made it easy to choose the right chiller for your aquarium. The JBJ chiller calculator does all the work for you. Just put in simple facts like tank size, desired temperature and heat-producing gear. The calculator does the hard math and recommend the right size chiller for your unique aquarium set-up.