For the amount of carbon to be used in your filter bag, I would say a half cup of carbon is all and replace it after a few days! I also wouldn't recommend using it constantly as it along with your skimmer will remove beneficial trace minerals and vitamins etc.
With carbon a little goes along way!!!
As for the coloration you are talking about it could be as Raven allerted to or uneaten food or another type of microalgae, or maybe even a reaction due to the carbon and medication or something in your tank water! _________ 125gal.w/Mag9.5 return(dual megaflow)>Mag7 pump Aqua Cev180skimmer.Wave2k Hamilton Reefstar(2)250watthqi(mh)pend.a Yellow, Naso Tang Red Lip Blenny Percula Clown Demoiselles Niger Trigger F. Wrasses Ceriantharia Orn.Shrimp and Stars Hermits Queen Conch asst. snails> Stars Zoos shrooms Montipora Brains Gorgonians Favia Turbinaria(large+small polyp) Acropora Xenia Tridacna (CroceaMaximaSquamosa) Leathers <35+75gal.reef tank as well> 
"IF THE PHONE DOESN'T RING...IT'S ME"  jb  |