Re: Humus, humic acid and natural chelating agents

> > Humic acids are removed by activated carbon.  There are clear 
> > implications for fate of trace elements in aquaria, perhaps Espe
> > 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 removal 
of trace elements is mediated by their removal as humic acid chelates.  
And I also know of some experimental determinations indicating that trace 
elements are not removed by activated carbon (in otherwise pure water) 
except at extreme pH values.