HMF vs. sponge filter???

[Rummy]

I am trying to understand the differences between a Hamburg Matten Filter and a regular sponge filter. The theory behind the HMF seems really good, but doesn't a sponge filter do the same? Besides the obvious difference in the size of the sponges; in the end, do they perform the same? I just don't get it. They both use air or a power head to move the water through a sponge. So how are they different?
Why would I choose one over the other?
It seems to me like the crud stays in the tank longer with a HMF than with a sponge (provided that you rinse the sponge daily). What am I not understanding?

I am also starting to wonder if I have too much redundancy in my filter. I have a 90 gallon tank with a 20 gallon sump. 12 semi adult (5-6.5") discus are in there with a clean-up crew. All is fine. But here is where I think I am redundant: I have two brand new hydor #3 sponges; a pre filter that gets rinsed daily on the overflow box (cheez, this guys can produce some slime!); a 25 micron bag (changed daily - slime); 3 sizes of 2" poret (45, 30, 20, if I remember correctly); then several bags of submerged ceramic and matrix and too many bioballs. The sump and the port are always clean because of the bag.
I got the bags on the basis that they will catch most unwanted organisms and prevent/decrease reinfection of my tank. Those bags are great at polishing the water. It is also nice to remove the crud daily by changing the bag daily. But doesn't this decrease the effectiveness, or the reason, for the poret in the first place?
In the end, all that surface area is also potential space to build up crud, isn't it? I really am wondering why I have all that stuff. I think the 20 gallon sump is a must, since there are so many fish in there. My test parameters are great. And I change 80% water daily or every other day. (Depends on how much life gets in the way.:)
If that bag weren't there, wouldn't I essentially have a HMF because of the poret?
I question all my setup, because there are so many of you that simply use a sponge filter and call it a day.

Are you guys dizzy yet? I think I need a cup of coffee to digest all of that.

Thanks

[roundfishross]

I have never tried the hmf in a large tank but for me in a 20g long for breeding purposes the filters would not move enough water to keep the tank evanly heated(with the heater behind the foam),this was even after adding an additional lift tube and oversizing the heck out of ther heater. I thought the clean look was awesome but it woulnt perform as well as a standard hydo sponge filter. If you ran a small power head it would most likely fix the problem but that defeats the purpose of a central air system if you gota run a power head in every tank :(


Ross

[Rummy]

Thanks for your response, Ross. That's good to know. Also, a power head takes up even more space! If the heat cannot be evenly distributed, that means the water probably isn't mixing as well either. Luckily for me, the water stays between 28 and 30 Celcius all year long. So heating is not an issue. Circulation certainly is, though.

[roundfishross]

Thanks for your response, Ross. That's good to know. Also, a power head takes up even more space!.


more electricity too!:p

[Rummy]

Yeah, heaters or not, the electricity here is, on average, 1.5 - 2x more than in the states. You are so right about the electricity.