In a saltwater aquarium, water flow is achieved two ways. A return pump is used to push water through the filtration system and is often called "return flow". Powerheads or "wavemakers" are used inside the display aquarium to create natural-like currents and create "internal flow". While each of these pump types is equally important, they are very different in design and function. When it comes to making the best pump choice for your aquarium, it's important to understand the differences and what features matter most.

Sometimes called a powerhead, a wavemaker is a special type of water pump used to create internal flow inside your display aquarium. The term "wavemaker" was coined because these submersible powerheads can be controlled to create wave-like water movement and varied currents which is the biggest difference over a typical water pump that is best used to create a constant and concentrated stream of water flow.

The Function of a Wavemaker

While we are still learning about the incredible importance of water flow, these are the main reasons for providing flow inside an aquarium above and beyond the flow from your filtration. 

  1. Suspend Detritus
  2. Deliver Nutrients to Corals
  3. Create a Realistic Habitat

Types of Wavemakers

Modern wavemakers have taken on a completely different design than your classic submersible pump and there are new designs popping up all the time. External propeller-type pumps that have an open pump cover with an exposed propeller instead of an impeller have proven to be much more effective for creating natural water movement throughout our entire display.  Gyre-style pumps are even more unique in design and create a completely different flow pattern. Regardless of design, all wavemakers fall into two categories.  

  • AC powerheads are controlled by an AC-powered motor which is intended for continuous duty. You cannot control the pump speed or vary the flow pattern outside of using a classic timer to turn the pumps on and off.
  • DC powerheads use a DC-powered motor and have now dominated the market because of the available control. You can control the pump speed and vary the flow patterns using integrated controllers. Some of these pumps can even be controlled using your smartphone and have some incredible features like operating on a schedule, feed holds, preset flow patterns, and temperature alerts. 

Flow Patterns

When choosing a wavemaker, the pump design is most important because of the flow patterns it is capable of creating. Understanding the different flow patterns is important so you can choose pumps that will best provide the flow you're looking for. Your tank dimensions and aquascape are the biggest dictators over what type of flow patterns you need. 

Flow Patterns

Conical vs Laminar Flow

A conical flow pattern is a cone-shaped pattern of flow that covers a wide area but doesn't travel long distances. External propeller-style pumps create these conical flow patterns. Laminar flow is flat, like a sheet of paper that travels farther in the aquarium. Gyre pumps are best known for creating a flat, laminar flow.

Wide vs Narrow

Just as it sounds, wide flow patterns are spread out over a larger area but typically don't travel as far in the aquarium. A narrow, much more focused flow travels farther but doesn't spread out as much.  

Effective flow pattern

Choosing the Right Powerhead

There are a few factors that come into play when it comes time to choose the best powerhead. Ultimately, you need to move the entire volume of water inside your display as efficiently as possible without blasting your corals with constant streams of strong flow. 

  1. Tank Dimensions: This is super important because different flow patterns are best suited for different situations. Laminar and narrow streams of flow are best used in long aquariums because they travel farther. Wide and conical flow patterns are more suited for short aquariums or situations where distance really isn't a concern.
  2. Aquascape: Try to imagine how the flow pattern will complement your aquascape.  Rocks will most certainly deflect water flow and change how that flow moves inside your display. Sometimes rocks will demand that you place your powerheads in different locations or simply add more powerheads to move the water effectively.
  3. Corals: The type of coral matters because SPS corals require much stronger currents than your LPS and soft corals. There are varying degrees of preference here but for the most part, we categorize them as high, medium, or low flow corals which is a direct result of where they are naturally found. For example, many SPS corals grow on the tops of rocks and in shallow reefs where currents are strong and turbulent. Soft corals and LPS are often found deeper or in areas where currents are less turbulent. You need to recreate these conditions in your aquarium to produce the most ideal environment and move corals to different areas of your aquascape based on flow needs.
  4. Pump Placement: Ultimately, pump placement plays a big role in where the pumps can effectively move water in your display.  If you place a pump right in front of a giant rock, it's probably not going to be very effective at moving water on the opposite side of your display or down in the opposite corner.  Placing pumps on the end of the tank will push water left to right, but does that effectively move water behind your aquascape? Should you consider a Gyre to move water across the top of your tank than something with a more conical flow pattern to move the middle across the rockface? The flow pattern the pump produces will often dictate the best placement to get water moving around your aquascape. 
  5. How Many Pumps: Most small reef tanks under 40 gallons can survive with a single powerhead. Larger tanks become more difficult and will often require 2-4 pumps to achieve sufficient flow. For tanks up to 48" long, start with two powerheads which will likely suffice for the first 1-2 years.  As corals grow, the flow dynamics will change and you can switch things up or add more pumps should you need them. In larger tanks, that are over 48" long, you will probably need 4 pumps to ultimately get flow where you need it.  

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Single pump position Dual pump position Four pump position

Learn more with BRStv: AskBRStv Tips For Perfect Flow

BRS Recommended

Ecotech Marine VorTech pumps have long been our preferred pumps because of the incredible control, slim profile, and unique magnetic design that allows for the motor to be mounted on the outside of your aquarium. Since you won't have a power cord or bulky motor inside your display, the pumps can be mounted almost anywhere and won't distract from the beauty of your tank. They run quiet and offer up some of the most versatile pump control on the market. They produce a semi-wide, conical flow pattern that compliments most any reef aquarium and with the use of the Mobius app, all of your VorTech pumps can be synced together and controlled from the convenience of your smartphone.