I have some funny, white, crusty things growing on my tank recently. They're small and sort of spiral-shaped. They started growing on my live rock, but they also seem to be popping up on the glass of the tank. They spread pretty quickly. Does anyone know what they are? Should I just scrape them off of the glass and hope they don't come back? Are they an indication of anything in particular? My nitrates are a bit high, so I imagine this is just a result of that fact -- nitrates being good for algae growth, I guess? I think of algae as more colorful and less...crunchy...than this, though. Anyway, lookingforward to any insights. Thanks!