What to Look for When Buying a Aquarium Pump?

If you are looking to purchase an aquarium pump, but wondering what to look for when buying an aquarium pump.

Look no further. You’re in the right place.

You’ll learn about the essential and important factors when deciding to buy an aquarium pump for your aquarium or fish tank.

An aquarium pump is probably the most important component of an aquarium system.

Why? You may ask.

Because an aquarium pump is the heart of an aquarium system that keeps the fishes inside it safe and healthy by providing oxygen it needs and by providing filtration that keeps the aquatic environment of the fish tank fresh and keeps the water clean and safe. An aquarium pump helps with the circulation of the water properly that ensures healthy fish for your aquarium.

You might get confused with all the various types of aquarium pumps available in the market. But the following detailed guide should help you choose the right one that suits your needs.

what to look for when buying a aquarium pump

What to Look for When Buying a Aquarium Pump?

You should consider several key factors before deciding on a specific model aquarium pump for your aquarium. Let’s take a look at these factors one by one:

Flow Rate – GPH (Gallons Per Hour)

This might be one of the most important factors when you are considering buying an aquarium pump.


Because this is directly related to the fish inside the tank or aquarium. Different fish species have different requirements of flow rate and if not chosen, correctly it may lead to unexpected health issues often death for your fish.

What is the Ideal Flow rate?

So how to determine the ideal flow rate for your fish tank?

The short answer is to learn more about the fish in the tank and their natural healthy habitat requirement.

For instance, you will need to carefully consider whether you have freshwater fish or saltwater fish in your aquarium. Their water requirement varies and it’s a big no-no to mix the two.

Freshwater fish tends to live better in lower circulated water whereas sea fish or saltwater fish tend to need the high circulation of water.

Freshwater Tank vs Saltwater Tank

Also, consider if it is a reef tank or live plant tank?

Reef tanks are those that contain saltwater and usually, sea fish are the resident of such tanks and these require a higher flow rate.

On the other hand, live plant tanks require a low flow rate. Why? Because less agitation in the water helps keep the carbon-di-oxide in water better as the live plants need it.

A rule of thumb to follow when deciding on the flow rate is that the amount of water it needs to push should be at least 4 times the amount of water the aquarium can hold.

For instance, a 50 gallons aquarium should have an aquarium pump with at least 200 GPH flow rate.

Noise Level

Simply keep this thing in mind – if you are going to get an external pump, even the little pumps generate enough noise to ruin your sleep at night or cause unwanted disturbance during day time, especially if you have your aquarium in your bedroom. Therefore, you need to consider the noise factor when buying an external tank pump.

Types of Aquarium Pump

There are two major types of aquarium pumps that are categorized based on the location of the pumps.

Submersible Aquarium Pump

Submersible pumps are submerged underwater and they are placed inside the aquarium or fish tank. These pumps relatively small in size and don’t take up much space. One major benefit of having a submersible pump is that you won’t have to do much DIY work to set it up. Unlike external in-line pumps that require you to drill holes on the aquarium. What’s more is that as these pumps are underwater, they don’t produce as much noise as in-line water pumps do.

In-Line Aquarium Pump

Functionally, there is no difference between an in-line water pump and a submersible pump. However, the difference lies in where they are placed. The in-line water pumps are external to the fish tank whereas a submersible pump is placed underwater within the tank.

The in-line water pump is placed outside the tank and hence, you need additional space for it to keep and you will need to drill holes on the side of the aquarium to attach the tube.

One benefit of using an in-line water pump is that it doesn’t produce heat inside the water as the submersible pump does and doesn’t take up space within the aquarium. Ideally, this type of pump is good if you have a very small fish tank.

One drawback of in-line external pumps is that they are a lot noisier than submersible pumps.

Head Pressure

Last but not the least, the head pressure is a factor that most people tend to ignore despite it being one of the most important factors.


Because it is directly related to the flow rate of the pump. Flow rate is the amount of water you need going back into the tank.

An aquarium pump will need to pump water through some heights of plumbing lines and through a few elbows as well. Which in turn reduces the flow rate to quite a bit.

What does it mean?

A Pump with a flow rate of 500 GPH will only yield about 250 GPH due to head pressure and for some turns in the piping system.

Therefore, calculating the head pressure of your plumbing is so important. Once you do that, you need to then compare it to the flowchart of your pump that you’re considering.

Choosing an Aquarium Pump in 3 Simple Steps


There might be other factors you need to consider such as your aquarium’s existing filtration system, size of the fish tank or aquarium, cost, etc. However, I have tried to include the most important key factors to look for when buying an aquarium pump and hope this may help you buy the most suitable one for your specific need.

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