I have used several powerheads over the course of the last two years. When I upgraded a 20 gallon fish tank of mine to a 40 gallon breeder, it became apparent to me that the current, rather small powerhead I had in use wouldn’t cut it. While reading reviews and looking at price tags of different powerheads, I stumbled across the Hydor’s Koralia line of powerheads.
Hydro Koralia powerheads are a little bit different compared to conventional powerheads, as they use a propeller to push water, not the usual impeller. This design gives off more of an indirect flow of water, instead of the normal direct stream given off by usual powerheads.
The Koralia Nano line (Hydor Koralia powerheads, only “nano”) has models with flow rates of either 240GPH or 425GPH and range in price from $20-28 a pop.
For my 40 gallon breeder, I purchased the 425GPH model. Like all other Koralias, the powerhead uses a combination of vibration cancelling suction cups and in/out of tank sandwich magnets to attach to the glass of a fish tank. Because of this, I have heard very little noise out of my Nano, which is virtually silent overall.
The flow rate of the Koralia is great, and has stayed consistent throughout its use. So far the only problem I have had has to do with the small ball found at the end of the powerhead. This ball is inserted into the a small hole found in the in-tank sandwich magnet/suction cup. This little ball n’ cup joint is what allows one to easily adjust the position of the powerhead. Over time however, the little ball has bent considerably, and has threatened to break on me. As long as I do not take the powerhead and magnet apart however, it should stay intact.
All in all, Hydor Koralia Nano powerheads are a great buy, due to their cheap pricing, overall quality and indirect flow.