No, it's a new tank and all new set up in October 2022 and we use r.o. water/saltwater from our fish store, still everything else: fish, seastars, shrimp, and crabs all seem fine. Maybe they were just a bad batch? We got them bc our hair algae is getting out of hand. We scrubbed a bunch off, and assuming everything else stays well, we're going to add an urchin to tackle the algae.