I bought my Mexican black king in early august and I have been keeping him on an aspen shaving substrate. I feed him outside of his tank so that he doesnt eat any of his substrate, however I read that a sandy looking substance in stool may be a sign of impaction. could he possibly be eating his substrate when im not around or could he have injested substrate at the pet store before he was purchased? other than noticing the sandy stuff in his stool he seems very happy and healthy! is he most likely fine?