Lack of water circulation in an aquarium, especially a reef tank, can lead to many problems. One of the problems is the reason so many aquarists decide to leave the hobby: nuisance algae growths. Poor circulation can also lead to low oxygen levels, uneven water temperatures (warmer and colder areas within the tank), reduced coral growth and even death in corals since they rely on water flow to bring food to them as well as whisk away waste.

This short article will teach you how you can improve water flow in your tank today. It will also give you a strong foundation for how to properly set up your next tank.

1. Powerheads

 These are the staple of water circulation in our aquariums and luckily there are many choices available. From "standard" nozzle output powerheads, like Hagen AquaClear or Rio Powerheads, to the "stream" or "propeller" style powerheads, like the Tunze Stream or NanoStream, Hydor Koralia and EcoTech Marine VorTech pumps. For an overview of some of the more popular powerheads, have a look at this article.

2. Closed Loop Systems

Closed Loop Systems allow the aquarist to create water flow throughout the tank without having to use powerheads within the system. Most of these systems require you to drill your tank. If you already have an aquarium set up, this may not be your best option. Items needed for a closed loop system include a hole saw (glass tanks require a diamond-coated hole saw), bulkheads & strainers (to prevent anything from getting sucked in), a Loc-line Modular Hose System (to aim the return water), PVC (rigid or flex) and an external pump. Pentair Aquatics Customflo system is a great alternative if you want to set up a closed loop system without having to drill your tank. If you would like more information about closed loop systems, send us an email for specific product recommendations for your system.

3. Maximize your return pump's flow

If you are using a sump system or wet/dry system, your return pump is a vital part of that system. How you plumb the return line can be just as important. The use of a "wavemaking" device such as a SCWD (pronounced squid) or Sea Swirl can take a unidirectional return and allow for a more random or chaotic flow within the tank (reducing the need for extra powerheads).

4. Flow Accelerators

These are another way to maximize your return pump's flow. They work best with pressure-rated pumps as they do increase the head pressure put on the pump. They will help increase the pressure of the flow within the tank but the actual gallons per hour will decrease somewhat.

5. Aquascaping your aquarium

The way we arrange the live rock and coral within our tank can have a dramatic effect on the flow achieved within the tank. By keeping a more open look and/or the addition of caves/tunnels within the rockwork permits better water flow throughout the tank and may reduce the need for extra powerheads to prevent "dead spots" or areas of no flow.

6. Wavemakers like the Tunze Wavebox

There are many types of wavemakersavailable. Some control powerheads and others oscillate the flow of the return pump. But the Tunze Wavebox is a little different. The wavebox produces "oscillating waves which produce water movement almost identical to reef zones." EcoTech Marine Vortech powerheads can also be programmed to produce a similar result.

Have you utilized other methods to improve the water flow in your aquarium? Share your experiences with us and other aquarium hobbyists. Thanks for reading!