Sponge filter question

Currently I am running an under gravel filter in my 29 gallon tank. It is being powered by a 2 outlet air pump with the carbon cartridges at the top of the tubes. I've read articles about these UGFs being bad as for trapping fish poop etc under the plates and the current not being strong enough to raise the debris. My question is this: If i remove the plates, and buy 1 or 2 triangular sponge filters what else would be required to make this thing run? could I use the uplift tubes that are on the UGF right now for the sponge filters? Also, how effective are the sponge filters? (I'm still going to be using my el cheapo hob filter as primary filtration) Also, how do these filters work? the air is just pushed down the tube then does the air come right back up the tube like it does in the UGF uplift tubes? Just curious.
TIA
-Stewie

[FancyGuppyGuy]

You could do all that. the chespo HOB will do little for bio filtration. The sponge filters will work great for Bio filtration.

ive had a UGF in my 29 gallon for well over 3 years have never had a problem I have 2 power heads on the uplift tubes.

Thanks for the reply FancyGuppyGuy. Thats what I was concerned about. The filter I have now has no way of holding bacteria except for the filter media. I thought maybe by removing the UGF's and replacing them with spong filters I could add better bio-filtration and somewhat better mechanical filtration.
Anyone else use sponge filters and can tell me more about them?

[BrianNY]

I run multiple sponge filters in all of my discus and pleco tanks for several reasons.
A sponge has so much surface area that it is ideal for colonizing the nitrifying bacteria. They are easily cleaned by rinsing in a bucket of tank water. I've always got a ready supply of seeded filters for setting up new tanks or transfering fish.

HTH

Thanks for the reply Brian. Just out of curiousity what type/brand of sponge filters do you use? Also am I correct in saying that the air is run down a tube within the airlift, then just bubbled out to the top just like the UGF airlifts? (same sort of idea?)
Thanks again
-Stewie