Water circulation is commonly discussed in the saltwater aquarium hobby in order to imitate the movement of waves, but not having enough flow can also be a problem in freshwater setups. Fish tanks (especially large ones) with lots of decorations or hardscape can develop dead zones where lots of debris collects and algae starts to grow. Increasing water circulation can help (a) stir up waste particles so they get collected by the filter, (b) evenly distribute nutrients for aquarium plants to consume, and (c) improve surface agitation so that fish have enough oxygen to breathe. Plus, some species like rainbow shiners and hillstream loaches are used to living in fast flowing rivers and may appreciate greater current in their environment. In this article, let’s talk about different ways to get better water circulation in your aquarium.
Water Circulation for Gentle Flow
If you have a smaller fish tank and/or only need slow to normal amounts of flow, then a regular aquarium filter can provide sufficient current for your needs. You can read our guide to fish tank filters about the many types of filtration – such as sponge, hang-on-back (HOB), and canister filters. All of these options are good for not only filtering and cleaning the water, but also creating current and surface agitation. Moving water at the top of the aquarium is important because it prevents oily biofilm from developing on the surface and encourages good gas exchange, where carbon dioxide (exhaled by your fish) is released into the air and new oxygen (for the fish to breathe) enters the tank.
If you have baby fry or a betta fish with long flow fins, sponge filters are one of the gentlest filters on the market. If you’re looking for something a little stronger, canister and HOB filters use motors to move the water and often have an adjustable flow valve to increase or decrease the output speed. In cases where you have adequate filtration but need a little extra flow in a stagnant corner of the tank, consider adding a simple air stone with an air pump. The bubbles from the air stone move water as they rise and create surface agitation when they pop.
If you have slow-moving fish or baby fry, a sponge filter can provide sufficient water circulation without stressing them out.
Water Circulation for Faster Flow
For larger aquariums or fish tanks that need faster flow, a power head is great option because of its versatility in multiple applications. A powerhead is simply a submersible water pump that sucks in water from the input and sprays out a powerful stream of water from the output. This device can be used to speed up water changes, create your own DIY filtration, and of course boost water circulation in your aquarium.
The Aquarium Co-Op power head circulates over 200 gallons per hour and has an extra-long, 11.8-foot power cord to reach almost any outlet.
How big of a power head do I need? Some websites say that water should circulate around a tank at least four times an hour, so if you have a 100-gallon tank, then you need a filter and/or powerhead that can move 400 gallons per hour (GPH). In our experience, the ideal flow rate depends on the plants and animals in your aquarium because some species can’t handle strong current and may become sick from all the stress. If you see that your fish and foliage are being whipped around the tank, choose a less powerful filter or power head. You can also try dispersing the flow by adding a spray bar or directing the output into a wall to decrease the kinetic energy.
How many watts does a powerhead use? Each model is different, but the Aquarium Co-Op power head uses 10 W of power to produce 211 GPH or 800 liters per hour (LPH).
Can a power head be used as a filter? Yes, power heads can be used as part of your filtration system. Many people use them to transfer water from their aquarium sump filter (which is a type of custom filtration) back into the fish tank. We also designed our powerhead pump to fit perfectly with the Aquarium Co-Op sponge filters. Normally, an air pump is used to run a sponge filter and gently draw water through the foam material. By attaching a power head to the sponge filter instead, water is pulled through the foam at higher speeds, resulting in greater mechanical filtration and clearer water. The method can potentially clog the foam more quickly so that you have to frequently clean it, but Aquarium Co-Op sponge filters are made with coarse foam that does not become obstructed as easily.
Attach a power head to the uplift tube of the sponge filter to strain particles from the water at a faster rate.
What’s the difference between a powerhead and a wave maker? A fish tank powerhead typically shoots a narrow jet of water in one direction, whereas a wave maker is meant to imitate the back-and-forth motion of ocean waves.
Where Should I Place My Powerheads?
Locate the dead spots in your aquarium by observing where debris is collecting the most or if blue-green algae is growing in certain areas. Using a power head can help disperse the decaying organics in those stagnant regions so that they get sucked up by the filter, thus making your water clearer overall.
If your heater has a “low flow” indicator that constantly goes off, consider putting the power head near it so that the heated water can spread throughout the rest of the fish tank and eliminate any hot or cold spots.
We like placing our power heads near the top of the aquarium so that they prevent oil slicks and agitate the water surface. When the pump is placed near the ground, it may stir up the substrate and cause cloudy water. If you want to hide the power head, try blocking it with a fish tank decoration or tall plants. You can also use a black background so that blends in better with the back of the aquarium.
Ideally, place your power head in a location that targets stagnant areas while staying relatively out of sight.
If you notice that the output of your aquarium filter or powerhead pump has decreased in strength, it may have gotten clogged over time. Simply follow the instructions in the manual to clean it out, and the performance should return to normal. For more information, check out our Aquarium Co-Op power head to keep your aquarium ecosystem healthy with proper water circulation.