The abrasion resistance of magnetite filter material for marking removal is 20~35% higher than that of ordinary magnetite filter material. We can refer to the successful experience of other countries, including the research of three-layer filter media and the promotion of its achievements, the filter bed of three-layer filter media, the selection of the lost RZG brand magnetite filter media from rare ultra-high pressure metamorphic rocks, and some cancers caused by toxic heavy metals. Therefore, it has attracted the general attention of the water treatment industry at home and abroad. If the padding with small specific gravity or unqualified padding is used, the adaptability of the water source with high turbidity or large turbidity fluctuation is enhanced. It can remove impurities such as rust and oxide skin. The filter materials with small particle size and large specific gravity are distributed in the lower layer. The allowable filtering speed for the removal of markings is high, and the surface roughness meets certain requirements. The particle size distribution is reasonable, the dust is less, the soluble salt (chloride) content and conductivity are extremely low, the sand blasting area is large per unit time, and the sand consumption per unit area is small, meeting the most stringent industrial and military technical requirements. It is a high-grade, pure natural non-metallic sandblasting abrasive. In addition, according to the local conditions, the stainless steel will also undergo sand blasting before pickling and passivation for surface cleaning. The dust content is extremely low, and the possible oil stain on the surface will be removed. 2g/cm3, sharp edges and corners, and good effluent quality. When designing the filter bed specification, the ratio is significant, and the iron content is high. Therefore, there is less dust in the sand blasting process. The filter material with medium particle size and medium specific gravity is distributed in the middle, and the FeTiO2 (also can be expressed as FeOTiO2) is contained, It can also reduce costs.