the biggest problem I see for everyone but the filthy rich is that the smaller model (G3) although it is rated for an 80g tank, in the tradition of every manufacturer out there, appears to be way overrated for a tank that size.
this is always the case. Manufacturers always overrate their filters. problem is, the small model is still $500 (Canadian).
so, who is going to go out and spend $500 on a filter for a 35 or 45g tank?
unless you are buying the filter just because its a new filter and you want to try it. which can also be the case. some people just love their toys. and thats cool.
but most people won't spend that kind of cash just because it is the latest newest thing.
Personally, I think this filter will be bought mainly by the reef enthusiasts. they are the demographic in our hobby with the most cash (if you can make a generalization like that).
if you go over to reefcentral for example and look at many of the tank build threads, its obvious that reefers seem to have a lot of cash to spend
