Bio-Gravel is a man made product of crushed expanded clay material. The material is coarse and gritty and a dark gray to purple in color. It is PH neutral and has no harmful chemicals so is safe for plants and animals. I have been using it for years in many of my projects such as aquariums vivariums and Wabi Kusa displays. The Bio-Gravel acts as a home form microbes in water and soil. Aquatic plants grow easily in the Bio-sand and I have used it as a top dressing for many display plants. Bio-Gravel has also been very useful as a soil or soil additive for growing plants. I have used it as the main substrate for some particular plants as well as an additive like per-lite for plant such as cactus, orchids, Amorphophallus and other aroids.
Bio-Gravel is very similar to the Bio-Sand and is sold in the same size bags. The main difference is that the Bio-gravel is larger around 5mm pieces which makes it a bit more airy for epiphyes and unable to compact with time is sold in large sealed bags each bags hold roughly 5 cups of Bio-Gravel
Bio-Sand and Bio-Gravel ship in flat rate boxes and cannot be combined with other orders. Up to 4 bags per flat rate box.