I verr recently realized I'm having an outbreak of vermetid snails, but I do not know where they came from. My FOWLR is 15 years old and I have never added any LR since. I only buy fish, no corals, nothing but fish. It wasn't until recently I started noticing them, only because it was pointed out in a previous post of mine. Before that I ignorantly thought they were non living "stuff" that just started appearingon the LR. Any ideas where they may have come from? Again, tank is 15 years old and didn't have this issue until recently. Thanks for any info.