I have a 55 gallon african cichlid tank that has alot of debris because I have 15 or so 4" fish. I have a eheim 2215 cannister and an aquaclear 70 operating. I have to clean the aquaclear filter weekly and the eheim monthly they get so dirty. I think I read somewhere that you can have one of these filters just do the biological filtering and one do the mechanical. Clearly, the aquaclear is easier to change so should i just put two foam filters in that and leave the biological to the cannister??