Hydor Koralia Evolution 850 Circulation Pump

The Hydor Koralia Evolution (model P29301) is a circulation and wave pump rated at 750-850 GPH. It runs on 115 Volts and absorbs only 5 Watts, which Hydor says is 50% less power and up to 20% more flow than earlier Koralia models. It is meant for tanks from 50 to 100 gallons, in fresh or marine water.

Shaft-less impeller

Most powerheads spin an impeller on a ceramic or steel shaft. The Koralia Evolution uses a shaft-less design, so there is no thin shaft to snap or wear. That also cuts down on the rattle older pumps develop as the shaft wears.

Mounting

A vibration-absorbing magnet and suction cup support hold the pump on glass or acrylic up to 1/23 thick. A sphere joint lets you change the direction of flow, so you can aim it at dead spots behind rock or across the surface.

Safe around curious fish

The design is smaller than older Koralia pumps with similar flow, and it includes a cable protector. Hydor lists it as ideal for tanks with urchins, puffers, parrot fish and triggers, animals that are known to chew or knock loose equipment.

Where it fits

• Extra circulation in a fish-only marine tank
• Moving water in a large planted or cichlid tank
• Pushing debris toward the filter intake
• A backup flow pump for a reef

Simple by design

There is no controller here, so the flow is constant. That is fine for many tanks. If you want pulse or random wave modes, a DC pump such as the Jebao ELW-20 wave maker adds that control.

Care and warranty

Pull the pump every month or two and rinse the intake cage and impeller to keep flow strong. At 6 x 3 x 3 inches it is easy to tuck behind rocks. Hydor backs it with a 2 Year Manufacturer Warranty.