It is true that you can't have too much filtration, but you can have too much flow. I know Fluvals have tons of flow, but as long as you don't have any slow moving fish (Betta, Angelfish), you'll probably be fine. I also have a 30 gallon tank with the Penguin 200 and Penguin 100, I'll probably be adding even more filtration soon! I actually have female Bettas and Angels, but I baffle the flow with plants, so if you do have slow moving fish baffle the flow.