I dunno, something funny in that German logic....although they make great cars!! LOL...Perhaps slower is better and they may well be right about that, but clearly our filters work and if you calculated out the flow rate thru your media I'd bet good money we aren't anywhere near what they propose....but ours obviously work. I don't have the article in front of me, but I recall it stating that a flow of 2-5cm per MINUTE was about optimal...which is a trickle by any pump standards I'm familiar with. OK, I know that's dispersed across a wide area, but that's the point, our filters aren't designed that way, so the flow rate thru our media is going to be waaaay higher. I dunno, I guess if it works it works, fast or slow......A guy could get crazy worrying about this stuff!! LOL
Actually the article I read on http://www.deters-ing.de
said to shoot for 5-10 cm per minute. They make a really compelling argument as they ran all sorts of tests to prove the effectiveness of this filter. I don't really see them trashing canister filters. When did it really become an us versus them discussion anyway??? Eheim is German, they make some of the best canister filters out there...
Most people I know in Germany use canisters. My brother has a tank with a HMF and one with a canister and he is equally happy with both.
I think the appeal of the HMF is clearly stated in the low maintenance and the "keeping everything in the tank" aspect. On the above mentioned website, for those of you who can read German, there is lots of data to prove the effectiveness of this filter as biological filtration method.
My next tank will have a HMF, just to experiment with.
How about pot scrubbers? They are pretty cheap.
I meant to mention this, too. Lots of people use these in sumps, they are dirt cheap and provide plenty of surface area for bio-filtration.