After seeing Chris' talk about SPS, noticing that it appeared everyone had quite a bit more flow than we do in our 90, noticing the prices of the Koralias, and getting some credit at EBay, we decided to buy a couple. We replaced some maxijets and now have 2 of the Koralia 4's in the 90 along with a PCX40 on a closed loop and an Eheim 1262 return pump. Best I can figure, that gives me about 40-50x assuming some head loss. I'm still planning to put penductors on the closed loop to get that up even higher. Oh wait... I'm supposed to be talking about the Koralias...
Plus sides:
-----Relatively cheap compared to the competition. I haven't had them long enough to know longevity and whether that price tag is a reflection of their quality, but they seem to be built pretty well. The "technology" is really nothing new and shouldn't cost more to produce, so as long as Hydor isn't cutting too many corners I don't think there will be many performance issues.
-----Definitely spreads flow out more than a traditional powerhead. I found that the flow doesn't necessarily come out as perfectly round cone from the propeller but instead more of an oval shape cone (if you put your hand in front of the pump there is more flow to each side than there is to the top and the bottom). I'm not sure why that is, but I imagine it has something to do with the design of the prop.
-----Relatively low watts (8.5w for 1200gph). I am now not even close to having temp problems since I replaced the maxijets (each using 20w for 295gph...ridiculously inefficient even more so then I realized until I typed this up) and they do pretty much match a tunze for watts used per gallon (Tunze 6060 = 11w for 1,585gph).
-----Magnet/suction cup and mount. It comes with a magnetic suction cup mount that I think works very well (uses a magnet and suction cup to keep the thing where you put it). It also has ball mount that is very easily adjustable in many different directions. For a lot of pumps you'd pay an extra $20 to get a magnetic mount.
-----More attractive. This may sound stupid, but I think they look way better than a Tunze and if I have to have a big pump in my tank I want something that looks alright.
Downsides:
-----At this point, they don't have a controller that I know of but I can't imagine this will be far off. You probably could something that would work but it might take some DIYing. They are not however recommended for start/stop wavemakers. Bottom line...I couldn't really run a Koralia 4 in my tank without bouncing it off of the glass anyway and with just subtle variablility in the flow of these things and having the pumps opposing each other from opposite sides, I feel like I get some pretty random flow... at the very least better than a standard powerhead.
-----Relatively unproven. They are new and it's scary to try new things. At the same time, I could buy a few of these before reaching the price of a tunze...
-----As with any big pump you need to put them pretty far from the surface because the agitation can pull air into the pump and/or stir bubbles into the water column from the surface. This just means that I had to put the pumps farther down into the tank (and farther into easy view) than I would have liked to. However, I don't see that as avoidable.
Bottom line... I've never had a Tunze but now having a couple of these I don't think I could ever justify the price tag to myself. In any case, they blow a standard powerhead out of the water on almost any level that they can be compared... so long as they hold up in the long run.
