It is one means to control dissolved dissolved organic compounds levels. But here is the rub. Which nutrients cause a problem? Which ones are in your system? Which ones are being removed by your skimmer? Which ones are being produced or removed by the substrate and live rock?
It seems that the GAC in my system is being used up but this does not seem to have any affect on the growth of cyanobacteria (looks bad, but otherwise I don't care), or hair algae, or macro algae growth (algae in my system is a welcome).
Very interesting, right? I have sneaking suspicion things are more complicated than "keeping nutrients under control".
