I’ve gotten a new blue tuxedo urchin. I have a lot of different types of algae in my tank however I read online that you need to give the urchin supplements of calcium or iodine. Can someone please explain to me what this is about? I don’t fully understand and when ever I google it, nothing comes up. I have a 55 gallon tank, with 40 lbs of live rock, 60lbs of live sand, two clowns, 1 orange spotted goby, 1 scooter blenny, 1 royal gramma, 3 green chromis, 1 purple firefish, 15 snails, 1 blue hermit crab, and 1 blue tuxedo urchin.