Humus, humic acid and natural chelating agents

Subject: Humus, humic acid and natural chelating agents
> > > Humic acids are removed by activated carbon.  There are clea
> > > implications for fate of trace elements in aquaria, perhaps 
> > > freshwater aquaria, in that statement.
> > That's why few aquatic gardeners use carbon in their systems ;
> Ah, but I don't believe that I've ever heard anyone say that the
> of trace elements is mediated by their removal as humic acid che
> And I also know of some experimental determinations indicating t
> elements are not removed by activated carbon (in otherwise pure 
> except at extreme pH values.

You are right that I've never heard it said that it was because of 
humic acids that carbon could remove trace elements, but 
regardless of the studies, amny aquatic gardeners have experienced 
situations where they were not able to keep iron levels up with 
carbon in the tank, and as soon as the carbon was removed, were 
able to maintain measureable iron levels.  Still, it's nice to 
know _why_ these things happen ;-)

Karen Randall
Aquatic Gardeners Assoc.
Boston, MA