The SDH top out deep sand tank filter adopts a deep sand bed design with a thick filter material layer, which can effectively intercept suspended particles, algae, organic matter and other impurities in the water, and improve the water purification effect. Top out design: The backwash discharge outlet is located at the top, which facilitates the rapid discharge of accumulated dirt at the bottom of the sand layer during backwashing, without the need to move the sand tank, simplifying maintenance procedures. Adopting scientific inlet water distribution and drainage collection design to ensure even distribution of water flow, avoid local rapid blockage, and improve overall filtration efficiency.