I guess I am lucky, being here in Arizona the pee spots dry quickly, we also have open air barns so they are not closed up with only a window and a door. As far as the sand goes as long as you feed Psyillium then you shouldn't have a problem with sand colic. Our horses are kept on dry lots here and we feed psyillium every day to every other day year round. Years ago I had a horse that had to have colic surgery (he rotated his colon 360 degrees). After they untwisted his colon they emptied it. I asked the doctor if they had found any sand in him and they said he was free of sand. This clinic also did a study on different products that are said to remove sand and Psyillium is the only one that did the trick. To each there own but I just wanted to say that sand is not all that bad if you take the proper precautions. We also feed out of 55 gallon plastic barrels that are laid on their sides and have an opening cut in them. Then on the bottom side we drill holes that let the dirt/sand fall through (since hay always seems to be a little dusty here). It has been several years and we have not had to add sand in any of the stalls yet.

I have used the pelleted bedding in the past for show livestock and it works great. But for our horses I find I like the sand over everything else that I have tried. For some reason my horse like to dig up the mats and play with them.