I watched a livestream the other day, dont remember who it was unfortunately, and they were all saying they dont use GFO and one of them said its bad for the coral. I have only tried it twice and both times with bad results. First time I put a tiny amount in a bag of carbon and and phosphates went to 0 so like a dummy I thought if a little is good then a lot should be better... I lost coral.... A couple of years later when I had high phosphates I figured I would try it again but only a small amout and instantly I saw my coral react badly so I pulled it. Sure seems to me like it is bad for the coral but some people really like it.

