Tropica Plant Care Aquarium Soil is a Japanese natural volcanic granulate material. Aquarium Soil naturally reduces your KH and pH value and enhances the ability of the plants to absorb nutrients. Aquarium Soil ensures good and active growth from the beginning and boosts the red plant shades and is a complete substrate, which can be used without any other types of bottom layer. Aquarium Soil is further an active bottom layer that lowers the pH value and slightly affects the water chemistry. We recommend that you change 25-50 percent of the water minimum twice a week during the first 4 weeks after establishing the aquarium. 3 liter bag.