How to Increase Water Circulation in Your Aquarium

Saltwater aquarium hobbyists often discuss water circulation to mimic waves. However, freshwater setups can have a lack of flow which can lead to problems. 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. Some species, such as rainbow shiners or hillstream loaches, are used to living near rivers and may be more comfortable with higher currents. In this article, let’s talk about different ways to get better water circulation in your aquarium.

Water Circulation to 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. A simple air pump and air stone can be used to increase flow in stagnant corners of the tank. The bubbles created by the air stones move water as they rise, and cause surface agitation when their bubbles 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 simply refers to a submersible water pump. It takes water from the input, and pumps out a strong stream of water from it. This device can be used for water changes, DIY filtration, or to boost the circulation of 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). Our experience shows that aquariums have different flow rates depending on their species. Some species are unable to handle strong current and can become sick. If you see that your fish and foliage are being whipped around the tank, choose a less powerful filter or power head. If the flow is too strong, you could try dispersing it by using a spraybar or directing the output towards a wall to reduce the kinetic energie.

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).

A power head can be used to filter water. Many people use them to transfer water from their aquarium sump filter (which is a type of custom filtration) back into the fish tank. Our powerhead pump was also made to work with 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. This can cause foam to clog faster, so you will need to clean it more often. However, Aquarium Co-Op sponge filters have coarse foam that doesn’t clog 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.

My Powerheads: Where should they be placed?

You can identify dead areas in your aquarium by looking for debris or blue-green algae growth in particular places. A power head can be used to disperse any decaying organics that have remained stagnant. The filter will then absorb them, making your water cleaner 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.

So that oil slicks are prevented and the water surface is agitated, we like to place our power heads near top of the aquarium. If the pump is too close to the ground, it could cause water cloudiness and stir up the substrate. If you want to hide the power head, try blocking it with a fish tank decoration or tall plants. Black backgrounds can also be used so the aquarium’s back looks better.

Ideally, position your powerhead in an area that targets stagnant locations while remaining relatively far from 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. Follow the instructions on the manual to clean it. The performance will return to normal. Check out our Aquarium Co-Op powerhead for more information. It will keep your aquarium ecosystem healthy through proper water circulation.