Clay based sand with high porosity that is ideal for bottom layer sand. Porosity is 30% higher than other sand, resulting in superior filtration capacity . Particles red-brown color, suitable for all kinds of plants and fish. Gex Roka Sand can also adsorb the minerals in the water, deodorant, allows for crystal clear water, and helps in controlling growth of algae. Gex Sand Roka also helps adsorb oxygen, keep the water in good condition. PH = 6.5 – 7.5