Hello James :)
The sand we put into a quarry depends on what we are going to do as an activity, jumping, dressage .... The amount of sand is also important, a greater height of sand is necessary for the obstacle. moreover it is often necessary to make additional arrangements with respect to the soil and there are countless different sand and choosing the right is complicated :). But I am convinced that it is best to approach a Professional because a career is an investment just like the sand that goes with !!