We know what it is and we're telling you its a problem. Like most people you've gotten bad advice and the wrong products from the pet shop. Seems like most UK members that come here have all been sold that stuff. Its dangerous. It is a bad idea to encourage a tortoise to eat dry sandy substrate to satisfy its calcium cravings. Think about that for a minute. And there are not little bits of limestone in the sandy areas in the wild, and your enclosure is not the wild. We are trying to save you from some serious heartbreak and guilt, and literally save your tortoise's life.Yeah it’s pro rep life substrate little bits of like stone that would be found in the wild same same as Arcadia earth pro arid that has volcanic stones that break down with the bodies natural acids