try...i put some red macro in my tank today and there was some green attatched to it as well for some reason and my blue tang was swimming around with a foot long string of green algae in it's mouth for a while until it ate it all up finally...did not want to share!
They're drops. My LFS mentioned it a couple of weeks ago. It's mainly vitamin C. I also put a couple of drops in the main food bottle that I use along with the garlic. I've been doing it for about 2 weeks now and I've got say she certainly seems brighter in colour and my chromis seem to be getting "bluer" in colour (they also eat the Nori!!).