How to Increase Water Circulation in Your Aquarium

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. Additionally, certain species such as hillstream loaches and rainbow shiners are used to living in rivers that flow quickly and may benefit from more current. Let’s now discuss different methods to improve 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. These options can be used to filter and clean the water as well as create 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. You canister or HOB filters, which use motors to move the water, are a stronger option. These filters often have an adjustable flow control to adjust the flow rate. If you need to add some flow to a corner of your tank that is stagnant, but have sufficient filtration, consider using an air pump with simple air stones. 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 a submersible pump that takes in water and then sprays out powerful water from its output. This device is useful for speeding up water changes and DIY filtration. It can also boost your aquarium’s water circulation.

The Aquarium Co-Op powerhead circulates more than 200 gallons an hour and has a 11.8-foot extension cord that can reach nearly any outlet.

What size powerhead do I need? According to some websites, water should circulate around the tank at least four times per hour. If you have a 100-gallon tank you will need a filter or powerhead capable of moving 400 gallons an hour (GPH). We have found that the flow rate is dependent on the species of your aquarium. Some animals can’t handle high currents and could 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).

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. Our powerhead pump was also made to work with Aquarium Co-Op sponge filters. An air pump is normally used to gently draw water through a sponge filter. A power head can be attached to the sponge filter. It will pull water through the foam at higher speeds. This allows for greater mechanical filtration. Clearer water can also be obtained. 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 powerhead to the uplift tube at the sponge filter to remove water particles faster.

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 find dead spots in your aquarium’s water by looking at where the algae is growing or debris is accumulating the most. 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.

Our power heads are best placed near the aquarium’s top to prevent oil slicks from forming and to agitate the water. 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, place your power head in a location that targets stagnant areas while staying relatively out of sight.

You may notice a decrease in the powerhead pump or aquarium filter’s output. This could be due to clogging. You can clean the filter by following the manual’s instructions. The performance should return back to normal. For more information, check out our Aquarium Co-Op power head to keep your aquarium ecosystem healthy with proper water circulation.