I,m limited on cash so the only my only filter is the emp.400 rite now its running with nothing in it so if I put rubble in both sides would I need to put a little lite over it and once i put rubble in it do I just leave it alone.I also thought about rubble on one side and filter floss on other which i would clean often and replace with new everyother week or so.Ido have about 25 pounds of LR in the tank.