AstralPool 11325 42" 26 SqFt Horizontal Commercial Sand Filter. AstralPool Horizontal Commercial Sand Filters are constructed in Jacksonville, Florida. Filters hold an NSF listing for working pressures of 50psi and test pressures of 75psi. Man-Way is a diameter of 16 Inch. Filters are constructed in six reinforced layers of laminated and filament fiberglass winding. Horizontal filters offer a vast range of surface areas and a 2 ft bed depth, providing space saving opportunities with NSF listed stacking capabilities. Standard and custom manifold systems, Semi and Fully Automated systems, Sand and Gravel required and sold separately.