The fluid bed Filters from Deltec are actually a must in your Sump. The optimum functioning of the filter material is achieved by using a fluidised bed filter from the FR series.
The FR series also called a substantial fluid bed with a bayonet cover to easily replace flter media. The water is forced into a central tube and is returned through a diffuser plate. Sponges applied on either side of the media portion to retain the finer particles.
The lid is equipped with a tap around the water flow and two hose pillars, can be easily removed or adjusted, so that hard pipes are also used.