Ok my frag tank has been sitting at zero nitrate and phosphate regularly for months on end and it is killing my coral but the hair algae has no problem. I add nutrients and the hair algae just takes off and it may grow 3-4 fold in just a few days depleting the nutrients of the tank within 1-2 days. I cant keep the nutrients up because of the hair algae. It is outcompeting all of my corals even at the zero nutrients it thrives for at least several months on end. Nothing will eat it. I have tried every cleaner.