I have a buddy with very sandy soil. He is growing most of his vegetables in containers in a so-so compost mix. He then takes the spent soil each year and amends the garden with it. Since his sandy soil would benefit from the addition of calcined clay, I was wondering if he could make a 5-1-1 with turface instead of perlite for his containers? I know the turface holds more water, but we are in L.A.