The skimmate that is pulled off can vary in color depending on several factors. How much air that you are getting into the skimmer, the time that the air is in contact with the water before bubbling out, and the type of proteins that are being pulled out by your skimmer. My skimmate ranges from a light brown, almost yellow sometimes, to a dark green depending on what is in my system and weather or not my skimmer is "tweeked" properly.
I have no knowledge of the type of skimmer that you are using, so I can't give a opinion on how well it would work for your tank.
Do a search on skimmer or skimmate and follow the links. Also try reposting this and the new hobbiest forum, or reef forum.
