Water circulation is essential in any aquarium, to ensure proper filtration, prevent the formation of anoxic or low-temperature regions, and deliver nutrients to stationary organisms. Power heads and aerators often provide sufficient circulation for a basic aquarium. In a planted aquarium, however, the water surface should be left undisturbed as much as possible to prevent loss of precious carbon dioxide and such devices should not be used.
Water pumps provide the necessary circulation both within the tank and through the filtration system, without unnecessary gas exchange. In a typical planted aquarium, water flows passively to the pump from a submerged intake where it is then propelled through the filter(s), and returned to the tank through an outlet below the water surface. The function of a water pump in a planted aquarium is exactly the same as that of the heart in the human body: pumping water rather than blood through a filter instead of the kidneys and liver. This analogy underscores the critical importance of the water pump in sustaining the health of a planted aquarium.
Not surprisingly, there are several types of aquarium water pumps to choose from, suitable for different types of tanks and budgets (see our selection at Julie's Pet Market). While perhaps not a glamorous part of setting up a planted aquarium, the selection of a water pump is one of the most crucial tasks to ensure a successful experience. Several criteria should be considered.
1) Flow rate. Water pump flows are rated in gallons per hour (gph) under free-flow conditions. For example, a 100 gph pump will circulate all the water in a 50 gallon tank twice in an hour. The presence of a filter (and its condition) will reduce actual flow. It is important to pick a pump with sufficient flow to ensure proper filtration. Conversely, an excessive water flow will turn your tank into a chaotic whirlpool. Usually, the filter manufacturer will specify the minimum flow rate needed for the water pump. The selected pump should exceed the minimum flow rate, but be comparable to it
2) Durability. A water pump is one of the few devices with moving parts in an aquarium, and therefore subject to wear and tear. Some pumps (e.g. magnetic drive) are designed without internal seals that can become corroded. This is more important for saltwater tanks, but well worth considering for a planted aquarium.
3) Heat generation. The electric motor generates heat that is transmitted to the water. Too much heat may contribute to wear and tear and is undesirable when you need to keep water temperature below a certain level.
4) Power consumption. A pump operates continuously and along with lights it is one of the main contributors to the energy costs of a planted aquarium. Prefer pumps with lower energy demands to keep costs down.
5) Noise level. Unless the pump will operate fully immersed, noise from the water pump is not to be underestimated as a factor in the enjoyment of your planted aquarium. You can often find information on noise levels on the manufacturer's web site.
In general, you should select the best quality pump you can afford. There are fewer sources of headaches in an aquarium worse than a poor pump: noise, overheating, and leakages occurring at the least convenient time can send you scrambling for a replacement. Having to replace a faulty pump - even with another poor one - after just a few months of operation makes this choice a false economy. The selection of water pumps offered at Julie's Pet Market includes only quality products to avoid you such problems.
