This gets asked about every other week, so I think it counts as a FAQ.
the answer: unless you create too much current (aka whirlpool) there is no limit to the amount of filtration you can have. You are just wasting space, electricity, and money after a while though.
the answer: unless you create too much current (aka whirlpool) there is no limit to the amount of filtration you can have. You are just wasting space, electricity, and money after a while though.