after a few drinks lol.. i was wondering an undergav ugf with no gravel an powerhead with bio balls and sponge diy or one of those store bought highspeed power heads dont know were iam going with this but would it work if that makes sence man sorry but iam going back to iraq shortly and it that sucks but i thaught it was a good question? 
there it is couldnt reply ha but its a ugf with no gravel ha ha ha a power head well one of those reverse power heads i think you now the big filter ones bbut used as ugf basicaly ugf used with no gravel sucked up through to a media then sponge or floss then through powererhead out do not worry no drinking down range 
