Hey everyone. I have a 12 gallon saltwater reef tank that I have had for almost two years. It's been a journey of ups and downs
. I noticed last month that I have something covering some of my live rock and wondered what it is and whether I should be concerned or not. It's kind of a light pink or beige-ish.... It is hard and doesn't scrub off with a toothbrush. It's taking over some zoanthids... I've been told it's sponge, but it doesn't seem to be like the pictures of sponge that I've seen around.... Input would greatly be appreciated.