The small surface film killer. In almost every aquarium, a film of microorganisms, dust, oils, and food fats forms on the water's surface over time - the surface film. With the EHEIM skim350 surface skimmer, you can reliably eliminate this film, achieving a crystal-clear water surface and higher oxygen levels. The EHEIM skim350, designed for continuous operation, is also suitable for short-term use. When used alternately in multiple aquariums, please ensure that no algae spores or diseases are transferred. The sucked-in bacteria and dirt particles accumulate in the filter sponge, which can be easily removed and thoroughly cleaned after use.