Diatoms form brownish coatings on plants, aquarium base and decorations. They occur when your water contains more than 0.4 mg/l silicic acid/silicates (SiO2). The silicic acid mainly comes from your tap water. It serves to develop the skeletal structure of the diatoms. To combat the algae, just remove the silicic acid from the water and they will die or have no opportunity to form.
Diatoms are neither toxic nor harmful. They even form a part of the nutritional basis for grazing cichlids in Lake Malawi and Lake Tanganyika. But as algae form brownish coatings which are regarded as unattractive we tend to remove them from our aquariums.
Distinguishing between diatoms and slimy algae
Both algal groups can look very similar. But when you take them between your fingers you can feel the difference: slimy algae feel greasy-slimy even after rubbing them longer, whereas diatoms feel rough.
SilikatEx removes silicate from fresh and marine water aquariums. It removes from the main nutrients the unwanted diatom algae (brown coatings), which often appear after freshwater has been added. SilikatEx Rapid also removes phosphate etc. and thus curbs the growth of other algae. The filter material creates biotope-like living conditions