When you hear the word redundancy, it’s usually used in a negative way. Redundancy is often characterized as a waste of time or money. However, when it comes to your fish tank, redundancy is the only protection your fish and plants will have if an important system fails. Aquarium maintenance service professionals always suggest system redundancy to safeguard your fish — and your wallet. Here’s a handy list of ways you can put redundancy to work for your aquarium.

Spare Parts

The simplest way to improve redundancy is just keeping extra equipment on hand. As anyone who’s had an aquarium for a while can tell you, everything eventually fails. Extra equipment may seem expensive and unnecessary when everything’s humming along, but you have to keep the true costs of extra equipment in perspective. An extra return pump might look like $300 sitting unused on a shelf in your closet. In reality, it’s an insurance policy that guards against the cost of replacing the entire aquarium’s contents if the primary pump fails. The peace of mind you gain by keeping extra equipment on hand is well worth the investment.

Avoid Overheating

When your aquarium heater malfunctions, it can quickly kill everything in saltwater aquariums. Unfortunately, there’s two different ways for a fish tank heater to malfunction, both catastrophic. Their controls can fail, and if they’re stuck in the on position, they’ll quickly cook everything inside the aquarium. If they get stuck in the off position, or if the heating element no longer works, the dropping temperatures will wipe out all but the hardiest of fish. The best way to prevent overheating in aquarium design is to employ two heaters. You can save a little money by choosing heaters that individually can’t handle the whole aquarium, but are powerful enough if used in tandem. If one breaks, you’ll still have one working while you get a replacement.

To take the concept further, you can use separate thermostats for as many heaters as you can. It’s a sure way to avoid overheating. All your heaters would need to get stuck in the on position to overheat your tank, which is very unlikely.

In addition to using thermostats and extra heaters, you can attach your other electronics to safety panels as well. For example, you can connect your lights to a circuit that will shut down if the temperature exceeds 82 degrees. Additionally, you could have another circuit with fans that switch on to blow air across the water in the sump.

The final element of preventing overheating is to make use of an exhaust fan. You can set this exhaust fan to activate when the humidity gets too high, or the temperature reaches 81 degrees. If you’re not sure how to set this up, your aquarium maintenance service tech can answer any questions you have about overheating issues.

Water Testing

The pH balance of the water in your aquarium is very important. While you can’t keep a redundant supply of water for your fish, there are a few ways to add redundancy. It’s smart to test your water using testing kits from different manufacturers. If they both agree, you can be pretty sure the readings are accurate. If they’re different, you should try a third brand to see which is out of whack. In addition to using your own kits, your aquarium maintenance service provider can test the water for you.


Redundancy on your skimmers is typically simple and relatively inexpensive. On larger tanks, you can use dual skimmers in creative ways. Dual skimmers allow skimming to occur even when you’ve shut down one for either mechanical failure or cleaning.  As well as making sure you’ve got constant skimming, you can set one skimmer to “wet” skim while your second skim extracts dry foam. If you use this method you’ll remove more skimmates, ensuring your system is more efficient.

Not only can you employ redundancy on your skimmers, but also on your scum cups. If you’ve got a large skimmer, you’re probably aware that the skimmer will occasionally overflow, particularly during power outages. One way to reduce the likelihood of this occurring is to use one-way valves. In addition to the one-way valve, you can use a delay timer that turns on after 15 minutes.

Top Off System

This one requires a little more effort and forethought, but you’ll be glad it’s in place if there’s ever a large loss of water in your aquarium. A top off system replaces water that’s evaporated or spilled from your aquarium. These types of systems add freshwater, even to saltwater tanks. This freshwater is set to fill automatically when it is depleted. Usually, this works fine, but occasionally the top off reservoir replacement does not stop. This will cause a rapid flood of fresh water to the tank. This drops salinity, and that can lead to big problems with your saltwater environment.

You can use a float switch as well as the sensor in your reservoir to double check the need for top offs. Either will stop the flow of water in the other malfunctions. Additionally, you can add a timer to the system. Set this timer to only allow the solenoid to come on long enough to refill daily water evaporation.

Smart Aquarium Design

The final form of redundancy is a second bottom in your tank. Glue the second piece of glass to the bottom of the tank. This will not only strengthen the bottom of the tank, but it will also prevent a dropped item from causing a crack that could cause anything from a slow leak to a catastrophe down the line.

If you combine these tips for redundant systems along with regular aquarium maintenance service,  you’ll guarantee a long life for your custom aquarium, and all the fish and plants it holds.