My blue crabs is in a tiny 5 gallon (getting 20 gallon today) and that's most of the problem but I don't know what the white junk is in his filter. It's little gobs on the filter media and it clogs the media up. I've never encountered anything like it before in fresh water and don't have any experience to draw from having a salt or brackish tank, so I'm clueless about this and search results didn't seem to turn up anything. What is it? Does waste turn white in brackish??