so heres a pic; well drawing. so what do you think i made like 10min ago. kinda ugly in the tank but should work great. blk is filter fiber and green is bio. i i got one of the small critter keepers and put a small pump in it 50-100gph. then some tubing. filled almost to the with bio meda( i used gravel and 2 thing of fulvu, the put top on and stuff with filter fiber and you got a great bio filter. cheap and easy. i tell you how well it works .