Before using a different ...

Published October 31, 2018 17:41 by Rafael Gay-de-Montella MSc PEng, Water Wastewater Treatment Expert, Oil-Gas, Tailings, Boilers, ZLD; Evaporators, Sludge

Before using a different material, I would consider if changing the sand particles diameter would not be sufficient to make this "porous" bed.
\in theory the intersticeal voids are function of the radius of the particles used in the bed.

But a more fundamental issue is to be reminded: Filtration IS NOT only the only result of straining a liquid by the interstices of the bed... filtration is much more than that.