How to Keep Your Saltwater Aquarium from Overheating

Published April 17, 2009 - RSS/XML Feed

By Robert Lashlee

One of the fundamental aspects of a successful aquarium is a stable environment which includes keeping your water temperature constant. Many fish keepers already know about the importance of keeping your tank warm enough. However, keeping your tank water cool enough in warm weather and preventing large temperature fluctuations is just as essential.

Why Should I Worry About Cooling My Tank and Keeping its Temperature Fairly Constant?

Temperature stress leads to the death of many marine animals. For saltwater aquariums, a temperature between 76 to 82 ^oF is recommended. Reef tanks do best at a slightly cooler 76 to 79 ^oF. This means that your tank needs to stay at a steady temperature between these ranges. Temperature fluctuations are very stressful for aquarium life. This is something to keep in mind during the warm summer months that involve temperature swings between hotter days and cooler nights (not to mention the temperature fluctuations that can result from having metal halides on during the day and off at night).

While fish are sensitive to temperature changes, species such as coral, shrimp, crabs, and starfish are much more sensitive to changes in their environment. Generally, you do not want your water temperature to fluctuate more than 2 ^oF in a 24 hour period. If these species are subjected to very high temperatures or large temperature swings on a repeated basis, they will bleach (in the case of corals) or die.

The level of dissolved oxygen in the tank is also something that gets impacted by water that is too warm. As the temperature of the water increases, the amount of dissolved oxygen it can hold decreases. This concentration is also influenced by the number of fish, coral, and clean-up crew (bio-load) you keep in your tank. The higher the bio-load, the quicker the oxygen in the water will become depleted.

How Does the Size of My Tank Impact the Temperature Fluctuations?

The larger your tank is, the less its water temperature will fluctuate. This is because it takes longer to cool and heat larger volumes of water. So, for example, imagine shutting off your metal halide lighting at night. In a small nano cube tank that holds 10-20 gallons, the water temperature can change quite rapidly. However, if you have 150-200 gallons, the 12-14 hours the lights are off will not be long enough to significantly cause the large volume of water to cool.

How Can I Cool My Tank?

There are several things you can do to reduce the temperature of your aquarium water and keep it fairly constant. All work to varying degrees:

· If you have an air conditioner, make sure you are running it. This will go a long way in keeping the ambient temperature around the tank steady and cool. If you do not have central air, you may want to think about investing in a window unit for the room the tank is housed in.

· Make sure that no direct sunlight from windows is shining in on the tank. Even closing the blinds so afternoon sun will not heat up the room the tank is in will help cool the room by a few degrees.

· If it is possible for your specific animals, consider reducing the amount of time your lights are on during the day. This is particularly true if you are using metal halide lights, as these get tremendously hot while turned on. This method will not help with temperature fluctuations, but it will help if your water is getting too hot.

· Fans are helpful at reducing temperature when placed inside your tank hood. You can choose to purchase fans commercially or fit your tank with fans liberated from an old computer. Alternatively, you can remove a portion of your tank hood and aim a fan onto the surface of your water. Be sure to cover your tank with a net to keep acrobatic fish from jumping out and be aware that your water will evaporate more quickly.

· If you house your pumps in an enclosed stand under your tank, it will also raise the temperature of your water through the bottom of the tank. Fix this by opening up the stand door and placing a fan so it circulates the air underneath the tank.

· The most sure way of cooling a tank and the best way to prevent fluctuations (unfortunately, also the most expensive) is to purchase a chiller. These machines work to cool the water itself and are the best at keeping the water temperature constant. Chillers are available in two forms: drop-in and in-line. Drop-in chillers have coils that cool the water in a tank’s sump pump. In-line chillers depend on water getting pumped into the chiller, cooled, then sent back to the tank or sump. In-line chillers can be set up away from the tank (helpful if you have limited space by your tank) and connected by tubes to your tank. Chillers cost anywhere from $170 - $2000, depending on the size you need. A temperature controller is necessary to control the chiller. These cost between $50 and $200 and are available in both single and dual-stage models. A single-stage model will only work your chiller, but a dual-stage controller will work for both your heater and chiller. For the handy fish keeper, it is also possible to build your own chiller. Directions and diagrams are available on various websites.

Conclusion

Keeping your water at a constant temperature is the best thing for your aquarium life. By checking your temperature often and implementing the above techniques, you can ensure that your tank does not suffer from temperature-related stress or fatalities.

Further Reading:

Read Related Saltwater Aquarium Articles

Saltwater versus Freshwater Aquariums: Learn the arguments for choosing to set-up either a freshwater or saltwater aquarium.
Saltwater Aquariums: A brief introduction to saltwater aquariums. Different categories. Pros and cons.
Reef Aquariums: An overview of the reef aquarium along with a short history. Online reef references.
Setting Up A Saltwater Tank System: What to Consider before Starting. Designing Your Salt-Water System.
The "Do Not Do" List for Saltwater Hobbyists: Learn what "not" to do when starting out with your saltwater fish or reef tank.
What is Protein Skimming?: Learn about protein skimming, why it's important, and which aquarists should use it.
Saltwater Aquarium Filtration: Filtration systems to use. Pros and cons of different systems.
Saltwater Aquarium Lighting and Heating: Kind of lights you need. Type of heating equipment to use.
Saltwater and Reef Tank Cycling: Tips on cycling your fishtank.
Getting The Tank Ready: Creating an ecosystem. Running the tank system.
How to Cure Your Live Rock Before Placing it in Your Aquarium: Learn how to properly cure live rock before placing it in your tank.
Creating an Aquascape and Choosing Fish: Creating an aquascape. Deciding on livestock for your tank.
Stocking Salt Water Reef Tanks: Learn how to select the right quantity and combination of fish for your saltwater aquarium.
What Are Good Saltwater Fish For Beginners: What makes a saltwater fish a good candidate for beginners?
Commonly Available Reef-Safe Fish & Invertebrates: Learn about commonly available reef-safe fish and invertebrates that are good candidates for your reef aquarium.
Establishing up a Clean-up Crew in Your Saltwater Aquarium: Learn how to properly select and establish a clean-up crew in a saltwater or reef aquarium.
Saltwater Species That Should Not be Kept by Beginners (and Sometimes not Even by the Experienced): Learn about saltwater animals that beginners (and sometimes experts) should avoid keeping.
Maintaining Your Saltwater Tank: Tips for maintaining a saltwater fish tank.
Getting Rid of Aiptasia in Your Reef Aquarium: Learn about aiptasia in the reef aquarium and how to get rid of it.
How to Remove a Mantis Shrimp From a Saltwater Aquarium: Learn how to properly remove a mantis shrimp from your aquarium.
Saltwater Fish Article Database: Articles on dozens of saltwater fish and appropriate care.