I just received a shipment of the new Hydor Koralia 4's tonight... and couldn't leave well enough alone.
Basic Koralia 4 impression: Cool looking pump, awesome swiveling magnet mount, very wide flow - wider than a MJ mod, about the flow of a "medium" MJ (ie. octura 1435). I don't understand why they made it so big... it's bigger than a MJ by a little bit, but the core pump stuck inside that cool housing is shaped like a MJ but MUCH smaller.
Time to play.
First thing I tried was swapping the stock impeller (puny magnet, decent sized and pitched prop stock) for a MJ 1200 magnet with an Octura 1440 on there. All I can say is WOW. Pushes easily double what the stock impeller does, and seems to push considerably more than the MJ 1200 that the impeller/prop came out of (though the improvement over the MJ may not be real... have to bag test it). There is plenty of room in the shroud for a much bigger prop, I just don't have any on hand to try right now.
I plugged it into a kill-a-watt and it is pulling 15 watts. The MJ 1200 with the same impeller pulled 20.
The hydor shroud is big enough to run a slightly shortened MJ mod impeller. The shaft size is the same as the MJ, so the MJ impeller fits perfectly. The only thing I would do to use this every day is add a stop for the propeller. For some reason the hydor doesn't seem to need one, but with the bigger prop it doesn't always turn the correct direction.
This thing flows like a full size tunze stream but looks slick and is only slightly larger than a MJ. Plus it's only $50!
Disclaimer: your mileage may vary, if it burns the house down it's not my fault, have fun
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