Will a canister filter work in only 5 inches of water.I want to have the intake in my wet dry filter.then the return fixed into the wet dry intake.therefore my wet dry filter has a filter of its own. Plus more water will be recycled.every time I add water into my filter it stirs up all sorts of junk that gets return to tank.so I figured that this would keep the portion around my return line a bit cleaner.but cant get cannister filter to work in shallow water????