Advantages and disadvantages of external vs submersible aquarium pumps

According to the size and type of aquarium you have, an external aquarium pump might be necessary to provide the power needed to to move the water over the filtration sufficient enough to maintain a viable environment for your fish. There are basically two types of pumps you can use for your aquarium - whether for running a filtration unit or for any other purpose. In addition to the external pump you also have the option of the submersible, and each has its uses specific benefits, advantages, and disadvantages for different jobs - both in freshwater and marine aquariums.

A submersible aquarium water pump lives underwater and is mostly used to power a protein skimmer, though protein skimmers are not so common in fresh water aquariums - they are used to provide water movement and to power a variety of underwater filtration units.

The external pump, on the other hand, sucks water from the aquarium, forces it through the filtration unit, usually a canister, and then back to the tank. In-line canister filters generally have to be of the pressurized type in order to maintain a fast enough filtration rate, and for that an external more powerful aquarium pump is needed. The submersibles are restricted in size and so are generally less suited to supply canister type filtration units.

Many people confuse the pump with the filter, though the pump can be used without a filter. The function of the pump is simply to suck water out of the tank and then force it back in again. Ideally, the water is forced through a canister filter before being returned to the tank. Or the water movement can be used for some other purpose - such as powering animated water features. Any filtering units that you happen to place in between those chain of events is up to you, but standard practices prevail.

The in-line external pumps have certain advantages over the submersible, though the latter is easier to install. The most obvious advantage is that size doesn’t matter! What that means is that with the submersible you have to be aware of the pump size in relation to the size of the tank whereas this is irrelevant with an external pump that also leaves more room in the tank for the fish!

Because they can be so much larger and contain a lot more filtration media then the external models, they can extract a correspondingly greater amount of waste, and thereby ensure a better environment for the fish through clearer and cleaner water. The flow rates are higher and because they are external to the aquarium, the motors of these pumps are not restricted in size. Another advantage of the external over the submersible pump is that the heat from the pump is kept away from the water. All pumps generate some form of heat energy, even if very small, and it is advisable that the heat does not disturb the fish’s environment.

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