OK, so I finally got my Hydor Koralia 4 on Saturday and have had it operating since.
All I can say is, wow this is a fine investment of $60!!
These powerheads are great! They are dead silent when operating, and produce a very nice, highly diffused flow.
Materials wise they seem a bit low-end (cheap), but seem solid in operation. The included magnet and suction-cup system is magic, and the positioning possibilities with the ball-joint are excellent.
Not nearly as powerful as the Tunze 6060 I have, and definitely more diffused flow compared to the Tunze, but a decent output for the size/cost. (And I realize that the comparison to the Tunze 6060 is outrageous, but I have one in operation so it's only fair to compare from my actual experience)
The Koralia 4 makes a tiny bit of chatter occasionally at startup (I have it on a timer, turns on/off about 6 times a day), but once operating you hear nothing.
Overall, I think these are a best buy! They output nearly twice the gph as a Tunze Nano 6025 for less money, and are slightly more powerful than even the Nano 6045 for nearly half the price! And the power consumption is comparible too.
With the great range of outputs/sizes, I think there is going to be some serious competition in the propeller-based powerhead arena now which is always good for us the consumer!
Thats my $0.02!
