How Many Hours Should You Run Your Aquarium Filter?

Aquarium filters are vital electrical equipment within an adequately designed aquarium.

Filters help to maintain and regulate water movement based on the desired water flow rate.

The filtration process also aerates the fish tanks introducing more beneficial oxygen into the tank. The oxygen generated will keep the fish and aquarium plants healthy since they have sufficient oxygen to carry out metabolic processes.

Most aquarium owners often consider turning off their filters due to some reason.

Among the significant reasons fish owners want to turn off their filters are its noise and high power consumption. This can make one uncomfortable and increase the electricity bill.

Before you turn off your filter, you need to know that the aquarium filter is designed to work throughout the day. Although there are instances where you need to turn off the filter, such as when you need to clean your aquarium tank or the water current is too high for your fish, you should run your filter all the time.

Should I Turn Off My Aquarium Filter Off at Night?

You should not turn off your filter at night because doing so will prevent adequate water movement and aeration, which can negatively impact your fish performance.

Besides, when aquarium owners asked if they should turn off their filter at night, they mean keeping it off for about 8 hours. This is enough time for poisonous ammonia to reach a very toxic level.

What will happen if you do turn your filter off all night?

Your fish will be exposed to toxic ammonia, nitrite, and nitrate released from the decaying fish food and wastes. These toxic compounds can hamper your fish’s growth and performance.

Now that you know it is good to leave your filter on continuously, you need to be conscious of wear and tear within the filter since it’s working every day.

You should prevent the filter from wear and tear if you want it to function for a long time.

The best way to prevent the filter from being damaged is to perform regular maintenance, during which accumulated algae and dust are removed.

If you maintain your filter regularly; you won’t need to worry about the filter’s functionality while working continuously. Some aquarium owners use their filters for two years without any issue.

Why Should You Not Turn Off Your Aquarium Filter?

The filter action helps to maintain the oxygenated water supply within the tank.

If you turn off the filter for a few hours, you will starve your fish of beneficial bacteria and oxygen. When this occurs, they may start to show symptoms of stress and illness.

The filter serves as the haven for beneficial bacteria that help to deplete the tank’s toxic ammonia, nitrite, and nitrate levels.

When the filter is turned off, the valuable bacteria may die due to a lack of oxygen. In contrast, non-beneficial anaerobic bacteria increase in number.

These anaerobic bacteria may harm your fish when mixed with the tank water as soon as the filter is turned on. This is possible because the filter action will generate a high water current.

Can I Turn My Filter Off For a Few Hours?

Experts don’t recommend turning off your filter because doing so will minimize the supply of useful bacteria-rich and purified water within the aquarium.

But suppose you have an active sponge filter, powerhead, or an air stone running within your aquarium. In that case, you can turn off your filter for a short period (1 to 2 hours). The sponge filter and powerhead will maintain water movement and surface agitation, thus, facilitating efficient gaseous exchange.

You need to know that turning off your filter can negatively impact your water parameters, and this will, in turn, expose your fish to illness.

You should avoid keeping your filter non-functional because the water regulation effect of your aquarium heater depends largely on your filter action since filtration is needed to disperse the heat generated equally within the tank.

Suppose you don’t run the heater for 24 hours. In that case, there can be a wide temperature difference between water near the heater and those farther away from the heater.

When a temperature swing occurs within the tank, the fish will be stressed, and some may die when the temperature swing is extreme.


You should not turn off your aquarium filter since it is designed to work all day.

If your heater makes a lot of noise; you should move it to another location to minimize the noise instead of turning off the filter.

You need to understand that fish like Betta fish prefer calm water; in this case, you may need to turn off the filter for some time to maintain a quiet environment.

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