alright i have a 10 gallon tank that has a couple fish in it. they may be getting a new 40 gallon tank soon but i dont know about that yet that trade is pending. any way i was thinking of making some sort of diy filter. i was thinking a five gallon bucket full of gravel just gravel nothing else pumping water to the bottom then having it come out a bulkhead fitting on the side near the top. what do yall think? how hard could it be? the rocks would act as mechanical and biological filtering right?