How often is it recommended to dump out and establish new fresh substrate in my enclosure?? currently using a cocoa coir and reptile sand mixture. I have been cleaning her cage daily to remove what feces and urates I can but some of the urates are drying up and becoming part of the substrate before I can get to them and I find them hard to get completely out (is this normal?). So I wonder how often changing the substrate out for fresh and new is recommended?? or when is too much of the dried up urates is too much to be healthy in her home??