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Chemical Filtration -Humic Acids
Rolando wrote:
> >is the best for removing yellow organic material from your water but
> >it may not be best to filter it continuously as it also serves useful
> >purposes to inhibit algae and bacteria. In excess it also may inhibit
> >some of your plants and some compounds like phenol are not healthy for
> >fish in large quantities either.
> I'm sorry you did a fly over on me (not hard with me) . Where does phenol
> come from?
I think what Steve was refering to here is phenolic compounds. The
yellow extract from soil/peat is a complex mess. Rather than refer to it
as "the water soluble acidic gunk we get from soil humus" Humic acid is
considered a little less embarrassing :). Tannins (the coloured stuff)
aren't much better defined. You can actually buy a jar of cleaned up
"Tannic Acid" from a lab supplier, It's generally used these days only
as a reference standard. The mess includes very small amounts of phenol
and heaps of complex compounds containing phenolic functional groups.
Like phenol they're toxic and acidic. Not knowing exactly whats in there
is frustrating to chemists so we tend to measure the bulk properties
instead. In fact a lot of the tests used to characterise/quantify the
"mess" simply assume we're measuring phenol. As Steve suggested in small
quantities these probably do more good than harm, at least for
rain-forest species.
Any soil chemists out there who can shed more light?.
Toado