I have had him about a year. He was doing great got him when he was about 2in. He grew to about 10in. I upgraded my tank that he was in to a larger tank my parameters are good nitrates are about 10 to 20 hard to judge color. Nitrates are 0 ammonia 0 and calcium is 360 mag. Is 1440. There was a algae bloom for a few weeks. Now it's going away but my urchins spines are breaking off but it's more like the tips of his spines and some are covered in this algae but mostly the tips of his spines. He still eats and moves around just kinda worried about him he has broke enough spines he's now more like 6to8in. Should I be worried?