[leebca]

Thanks for posting.

A tube from the top of the center of the filter will act like a riser. Instead of a mechanical draw, an airstone near the middle of the filter running with air, will draw water through the sponge. The air mixed with water in the tube is 'lighter' water than the surrounding water and that water rises in the tube. This action draws water through the filter. It is the same principle hat an undergravel filter operates. You might check out how they look and how air stones are used in those 'riser' tubes.

The sponge filter operating with the air and drawing water through the sponge, is put into the sump or established marine system. That is all that is needed to 'seed' the sponge with the desirable bacteria. However, like the first cycle on your new aquarium, the seeding takes a few weeks.