I have a 75 gallon guppy/shrimp/mystery snail tank that I need to add more filtration to. I currently have 2 Marineland Penguin Filters (350gph) on the back with sponge filter intakes but would like to upgrade by adding in a canister filter. I previously had Penn Plex canister with a sponge filter over the intake, but it barely was able to push water back into the tank and wasn't doing much of anything. Anyone have a suggestion on how to implement better/more filtration, ideally with a canister filter, but so that it wont suck up any fry or baby shrimp? Would even just rubber banding panty hose over the intake be viable solution?