Beware when buying sand for a sandschool. We were sold some sand by Cemex UK which is totally the wrong sand for a school. We told them we wanted silica sand for a sandschool and they sold us medium grade. This is useless when it is wet because it moves when you ride on it and even worse when it is dry as it rides too deep. We have since found out that we should have been supplied fine grade sand - this compacts well to give a safe riding surface. We have spent a lot of money on sand that is totally useless and not safe for the horses!!