i had a tank full of that coral , i loved the way it looked till it would get brown and look bad, i did use bleach, i put it in a bucket and let it sit then would just wash it and put it right back in and never had any trouble, but for a while there after i bleached it i would take the coral out when i started to look bad and ran hot water over it and i took it away, i did this before the alge got really bad and it worked, it will save from have to use so much bleach