I learned today that it’s not good to use rock salt in aquariums. Lots of people think it’s the same as aquarium salt. It’s not. Aquarium salt is taken from the purist fields. Rock salt is not meant for food so it’s scraped out of the edges of the salt fields. So there’s all kinds of stuff mixed in. Often contains impurities like nickel and lead. Just wanted to caution everyone. I had started using it but going back to aquarium salt.