Hydor Koralia 12 Volt are a good all round powerhead for today's aquariums. They come in five varieties to suit and level of water flow you require. The Hydor Koralia 12 Volt plug directly into the mains via a normal power socket and provide a constant flow of water. The amount and type of Koralia which you need will very much be determined by how much water flow and turbulence you want to achieve in your aquarium.
The Hydor Koralia 12 Volt flow direction is fully adjustable via a ball joint on the magnet. These are very low power consumption and the magnets are suitable to use on glass up to 1/2 inch thick.
Technical Specs
Koralia nano - Flow Rate: 240 gph - 3.5 Watts
Koralia 1 - Flow Rate: 400 gph - 3.5 Watts
Koralia 2 - Flow Rate: 600 gph - 4.5 Watts
Koralia 3 - Flow Rate: 850 gph - 6.5 Watts
Koralia 4 - Flow Rate: 1200 gph - 8.5 Watts | 
