Hi, I'm new As the topic says, I have some kind of white growth on my LR that appears to be growing and spreading, it's not slimy or squidgey to touch. Nitrite: 0.20 Ammonia: .20 PH: 7.5 Tank Size: 155L Age of set up: Month and a half Inhabitants: 2x Fire Shrimp, 2 x Hermit Crabs Anyone have any ideas what this could be? Good / bad? The guy LFS said it could be some kind of sponge, but I got the distinct impression that "he just worked there" and didn't really know. He suggested I ask on a forum on internet. Many thanks in advance for any advice / help given!