Looks like bryopsis to me take the frag plug and rock its on out if you can and get it out If its a rock you dont mind doing without and isnt too big if it is indeed bryopsis is the easiest way to control it- is pretty hard to control but if you get it all out will be taken care of.
Looks like its only on a small rock- id ditch the rock, pretty sure that would take care of it.
If only on the plug home run-- take it out- scrape it off with a razor completely and put the plug back in I would imagine.
Sevtt is a great one to ask on how to deal with it.
Ok good luck man. If your using the rock in your upgrade from the 38G ANY rocks that its on dont transfer- no use introducing it to your new tank. Best of luck and keep us updated on how it goes.
that crap grow fast, personally I would toss the frag, and not just any MAG will work to cure it. You need the Kent Tech M, there is some sort of impurity in it that kills it for whatever reason. Takes about 3 months to do. But like Jimmy said earlier just take the frag and the rock and get rid of it. It will save you money and headaches in the long run.
great guys it was just a frag i bought like 4 days ago i dont think it spreads that fast it was on the frag i just scraped it off ill keep an eye on that frag
Motor I didn't even read your thread, I just posted what I know from my own little experiments and from people I have spoken with that had the problem.