Cali sand is digestible the problem is that if to much calcium is taken in it can mess up the chemical balance in the tummy and prevent proper digestion of food hence forth causing impaction on dinner or atleast I have read that several different times. As for what subrate you keep your animals on that is purely up to you after weighing all your options and making up your own mind. I have kept beardies on cali sand and regular sand. The only reason I stopped was I got tired of the mess Sand makes and Cali sand was getting to costly repti carpet is much easier to clean and maintain when upkeeping 5 beardies 3 leos's 2 frog eye geks 5 Bps 2 RTB 1 King snake 1 JCP and a Rainbow boa. (yes I am a slave to my herps) but I love it and wouldnt have it any other way.