Where to Place Powerheads in Freshwater Aquarium

Where to Place Powerheads in Freshwater Aquarium

Powerheads are used in freshwater aquariums as a water circulation pump, especially in large aquariums.

       They are responsible for helping with water movement, preventing the accumulation of residues in certain aquarium places, which can lead to areas without oxygen, giving rise to ammonia peaks, algae, cyanobacteria, and parameter fluctuations that compromise the quality and hygiene of the aquarium; consequently, the general health of fish and other inhabitants.

       This equipment also has other functions such as imitating running water environments or strong flow; natural habitat of some fish species.

       It is crucial to know the correct place to place your powerhead pump, as it can cause excess water circulation, harming the integrity of fish and plants.

       In this article, we will address and elucidate the main doubts of the hobbyist concerning the best place to place your powerhead in a freshwater aquarium.

What is a powerhead

       The powerhead is a pump inserted submerged in the aquarium. It generates a flow of water, causing the water to be moved throughout the aquarium, thus preventing the formation of stagnant areas and promoting internal circulation and gas exchange with the external environment. These gases are (mainly) oxygen, nitrogen, and carbon dioxide.

       Despite the function of moving the water column, allowing a greater exchange of gases between the aquarium and the atmosphere, indirectly causing an increase in the filtration efficiency in the aquarium, when it is not associated with a filtering system, the powerhead is not capable of removing impurities from water or transform ammonia into nitrites and nitrates. This equipment does not act as a filter.

       While the powerhead can be used as an integral part of filtration systems, the filters remove impurities from the water, leaving it always in excellent quality and suitable for the fish that live there.

       In addition to its complementary use to maintain the excellent health of the tank, this type of pump is also widely used for environmental purposes, creating a rapid flow of water.

Dimensioning your powerhead

       A lowpower aquarium powerhead will not affect a large aquarium. In the same way, a small aquarium does not need a powerhead with maximum power, which can harm the animals due to excessive agitation in the water.

       As you may have already noticed, the choice of aquarium pump is directly linked to the fish you intend to have. Do a lot of research before setting up this environment, and be sure to talk to an expert to find out what you should have in the aquarium so your fish can live well.

How to choose the most suitable powerhead

       The choice of powerhead depends directly on the characteristics of the fish tank itself, such as its size, the species, and the fish population it holds appropriately for the health and well-being of the animals.

       When choosing the correct powerhead model, remember that they are all rated for different tank sizes, with this classification visible on the packaging.

       However, keep in mind that this rating is in terms of tank liter within the standard measurements; if you have a taller, longer, or hexagonal tank, you may need to resize your gear.

       With all the information regarding your system in hand, you should choose the pump that has the power compatible with the type of aquarium you are setting up and what you need.

Which powerhead model to choose?

       Several models of circulation pumps are on the market, with several different powers and features. You can even find models with programmable modes capable of regulating their power and flow according to the needs of your aquarium. There are also models with speed regulation, wave timer, wave flow for day or night only, flows directed from right to left or vice versa.

Choose the one that best suits your system.

Why use a powerhead in my freshwater tank

       It is straightforward to understand why using such a pump in the system, its advantage is to cause a disturbance in the water, thus breaking the surface tension, which (by osmosis) promotes gas exchange, leading to CO² molecules (and other gases present in our aquariums) to the outside, and O² (and other atmospheric gases) to the tank. This will promote beneficial gas renewal to the system.

       In addition, due to the physical movement of the jet-driven by the water outlet and uptake by the pump carried out in the water column, it will create a constant flow of water inside the aquarium in that direction, where all areas will receive renewed water; thus avoiding anaerobic areas in the tank.

Where to place the powerhead

       Understanding the theory of its operation, we see that the water outlet must be positioned according to the aquarium’s architecture, preferably in the middle part of the tank, thus increasing its efficiency, which fluid mechanics explains. Therefore, placed in the middle of the water column and preferably in the physical center of the tank, it will cause all areas and corners to be affected by the flow generated by the pump.

       You can insert a powerhead on top of the water column to simulate waves, which will help a lot in gas exchange, increasing the oxygenation of the water. Then you can insert another powerhead for the internal movement of your aquarium. If your aquarium is large, you will need to use more pumps scattered around the inside so that the water does not remain motionless anywhere. But always be very careful with the power of the powerheads, not to cause an exaggerated movement.

       Suppose the powerhead is used in an aquarium where there are many places with little water movement and still water areas. In that case, it is interesting to position the equipment in the lower area of the aquarium, taking care not to disturb the substrate and plants. The flow of water near this region will lead to more oxygen and moving possible debris trapped there without being consumed by bacteria.


       Although there are no specific sizing rules when choosing a powerhead – it depends a lot on what it will be used for and how the aquarist designed his system – we advise selecting a powerhead that is silent and has an adjustable flow, where its maximum is slightly more significant than the necessary; this allows for future expansions without equipment changes.

       The correct use and mainly positioning of the powerhead are given concerning the general characteristics of the aquarium. The hobbyist must know that success in sizing and choosing the right equipment will bring a beautiful and lasting success story when perfectly adequate to his system.

       The powerhead is one of the most used equipment in fishkeeping; its advent was nothing more than a revolution. It can represent success in the hands of some or a disaster in the hands of others; because of that, in this article, we cover everything you need to know to make your experience pleasurable and beneficial, minimizing mistakes and increasing successes.


        Arantes, F. S. Criteria for selection of circulation pumps used for aquarium hobby based on eco-efficiency. 2020. 60 f. Dissertation (Master’s Program in Production Engineering) – Universidade Nove de Julho, São Paulo. doi:

        FOX, R. W.; Introduction to the Fluid Mechanics. 6 ed. Perdue: John Wiley & sons, inc.,

2004. 787 p.

        HELFRICH, L. A. & LIBERY, G. Fish Farming in Recirculating Aquaculture Systems (RAS). Available ar: http://www.aces.edu/dept/fisheries/aquacultura/documents/recirculatingVt. pdf.      

        LIVENGOOD, E.J.; CHAPMAN, F.A. The ornamental fish trade: an introduction with perspectives for responsible aquarium fish ownership. Electronic Data Information Source (EDIS) of the Institute of Food and Agricultural Sciences (IFAS), University of Florida, USA, n.16, p.1-8, 2007.

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