The Deltec fleece filter cleans the aquarium water via the fleece and filters out turbidity and dirt from the water. If the fleece is loaded with dirt and saturated, the water in the Deltec fleece filter rises and the float switch starts the gear motor, which continues to rotate the fleece roll. Once the roller is used up, the gear motor lifts the pulley out of the magnet holder. This can drain the water and stop the engine. Now the roll can be changed easily and the water filtration can be continued. The emergency overflow also ensures that the water is returned in a controlled manner when the water level in the filter should rise.