Dean -
I used to have two Emperor 400's on my freshwater tank. There are two rotating wheel on the front that the water sprays on. Those wheels should be removed. The other filters that have the filter floss material on it are ok, but you should rinse them out fairly often. If you have RO/DI water, rinse them with that or if you use tap water let it sit out and dry. Putting the filter pad back in wet with tap water will introduce other chemicals into the tank water.

Chris