SUBSTRATpro consists of pearl shaped sintered glass. The spherical shape gives a high bulk density. Thus the whole of the volume in the filter (filter baskets or modules) can be utilised. Also the optimum surface of the beads provides intensive colonisation of the important purification bacteria.Due to the high number of bacteria, peak nitrite loads are more easily reduced and the maintenance intervals of the filter material are longer. EHEIM SUBSTRATpro is suitable for fresh and marine water, is washable and can be reused.