All algae (except blue-green algae, which are not actually algae but cyanobacteria), are exacerbated by high nitrate (NO3) and phosphate (PO4) levels. Diatoms are an exception to this and form unsightly brownish coatings on gravel and decoration. They only occur if the water contains silicic acid (silicates, SiO2). They build their skeleton from this substance, and, incidentally, you can view their incredibly beautiful skeletal shapes under the microscope. But they’re only beautiful under the microscope! In most cases, the diatoms disappear with a little patience once the silicic acid present has been used up. Sometimes, however, it needs a helping hand and then we use a special filter material to remove the silicates ( JBL SilicatEx Rapid ). With the help of a silicate water test you can check whether your initial water already has higher silicate values ( JBL PROAQUATEST SiO2 Silicate ).
