I have that filter and there are several ways to slow down the water flow. You can add a prefilter sponge on the intake pipe. The thicker the sponge the slower it intakes water and the slower the out flow. You can also add a piece of sponge in front of were the water enters the filter on its way to the filter media. There is a hole inside the filter housing right above where the intake pipe is. Just cut a piece of sponge to fit in there and it will slow down the water. It is easy to baffle the outflow too. Just cut a strip of plastic canvas, sold in craft stores, and attach suction cups to each side. make a circle around the outflow.
Works great.