The weight of the pumice are light, it will float on the water, you can tie a rope above the pumice , then dragged into the water, made the suspension landscap
The base material of grow plants, pumice surface has many holes and can be contact large area, can absorb the water harmful bacteria and heavy metals, conducive to plants climbing and take root, plants itself can dissolve mineral not only conducive to the fish grow, can also provide fertilizer for the plants