Water Movement in Freshwater Aquarium

When considering the setup of a aquascape aquarium from scratch, water flow must be one of your most important considerations. Unlike tropical fish, aquarium plants cannot move about the fish tank to find nutrition. Live plants can only utilize the aquarium fertilizers and CO2 (for those of you who use CO2 reactors) when these substances make physical contact with the plant leaves. So how do we achieve that and what do we need?

In nature, water current brings plants, fishes and other invertebrates food, oxygen, nutrients, and movement that they need to grow. Water movement in your freshwater aquarium will do this task. Not only that, water flow in aquarium is crucial to the viability of your freshwater tank. Currents help feed and nourish inhabitants, wash away waste products and sediment that promote damaging algae growth. Incorporate one or more of the following three types of water movement to create the best conditions for your aquarium inhabitants.

Laminar flow is the most common in the aquarium and simply means that the water is moving steadily and in only one direction. It is most often produced by powerheads. Depending on your aquarium setup, you can create laminar flow only or multi-directional flow with a powerhead by adding PVC pipe and fittings to the outflow. Or, implement an oscillating powerhead, which rotates within the aquarium and directs water over a wider area. Several oscillating powerheads, used together can create beneficial turbulence. The Switching Current Water Director, installed on the return of your main filtration, contains a pressure-activated switching valve that effectively splits your return line into two alternating outputs to create beneficial currents.

Surge is similar to laminar flow, only stronger, for a shorter duration, and followed by a weaker reverse flow. Think of the sudden movement of an entire school of fish in a single direction, followed by their sudden return to the initial location once the surge passed. Like turbulence, surge is very difficult to replicate.

Turbulence is the random swirling and flow of water in multiple directions. This happens when currents collide with each other. Turbulence is extremely desirable and difficult to replicate. Some techniques commonly used to generate turbulence is by turning the powerheads on and off randomly using electronic wavemakers with several standard or oscillating powerheads. Of the three types of aquarium water movement, turbulence is the most desirable and the most difficult to replicate.