To this day, some people incorporate closed loops into their systems, especially folks in the large to very large tank owners bracket, but for most of us, this method of flow-making became pretty much obsolete overnight when the first true powerheads entered the market.Ī loose definition of a powerhead (loose because the standard design has been challenged with success on numerous occasions), otherwise known as a wavemaker, a wave pump, or a propeller pump, is that it is a type of submersible pump that transfers the energy of the motor by pushing, or propelling, the fluid outwards from the center of its rotation by means of a cylindrical impeller designed to move large amounts of water using a small amount of electrical energy. One, or preferably multiple, water pumps were plumbed within the display aquarium and plugged into a switching power bar, or wavemaker if you will (remember those Aquarium Systems Natural Wave Wavemakers?) which turned them on/off at pre-programmed intervals, providing multiple points of short-time bursts of jet-like flow in various areas of the tank.
![wavemaker for reef tanks wavemaker for reef tanks](https://ae01.alicdn.com/kf/HTB1TbrHQpXXXXbQXVXXq6xXFXXXP/110-240V-Jebao-RW-8-RW-8P-Wireless-Wave-Maker-Pump-Aquarium-Powerhead-Wavemaker-Circulation-Pump.jpg)
In a typical reef tank of yesteryear, the so-called closed loop systems played the role of wave making devices. With a reef tank, powerheads not only keep the rocks clean of ammonia-producing detritus while giving corals a chance to catch their dinner, but most importantly, they create water movement that is essential for gas exchange in the environment, in turn providing corals with oxygen to respire. In my planted tank days, I didn’t even own a powerhead until much later (a single Koralia as in the picture below), all my flow needs were met by duo canister filters, their outlets located at the opposite rear corners of the 75g, plant infested underwater jungle. I remember coming from a freshwater background into reefing and being amazed at how much flow was needed to keep corals alive, compared to the planted tank I used to own. Some corals like more, some less, but all need the “artificial” current a propeller pump creates in order to survive. You simply can’t keep a reef-dwelling coral for long if you don’t provide it with enough oxygen transporting flow.
![wavemaker for reef tanks wavemaker for reef tanks](https://cdn.shopify.com/s/files/1/0360/6301/9052/products/Hydor-Koralia-WM_1024x1024.jpg)
If you don’t, well, you better get one (or two, or more…) because there is no reef tank on this planet that looks good without proper water circulation. If you happen to be the owner of a reef aquarium hosting live corals, there’s a good chance you also own a powerhead.