I use sand in my stalls and I live in AZ so my horses are on dry lots also. We have to worry about the horses getting sand colic just off of the ground. But if you are worried than feed psyillium. Psyillium is a natural fiber and the only one proved to work (others claim but have never had studies to prove it) I have had one of my horses go to colic surgery for a twisted gut and while they where in there they always dump the gut (Flush everything out) There was no sand found in my horse and he lives on a dirt lot lives in a sand stall and eats off the ground, and is fed Psyillium on a regular basis. Special Tan, You do not smell the urine like with shaving. I have a horse that goes potty in the same spot, so about once a year I clean out that particular corner and add new sand, but the good thing is that side of the stall gets sun so it helps dry things out also. Sand is not such an evil if you take the right percautions, and sand is way more beneficial for the horse over all. hope this helps.