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> From: Greg Morin <greg at seachem_com>
> Subject: Re: Aquatic Plants Digest V6 #71
> > Hmmmmm. I infer from this that the stuff is highly effective
> >in removing metal ions, but that the typical dose is so low that your
> >trace elements swamp it. If that is the case, it won't remove the heavy
> >metals too well if there is iron there - the iron will take just about
> >all of it.
> > I'd like to hear another explanation....
> Close, let me try to explain again ;-)
> I'm just going to use arbitrary values here to make an illustration.
> Let's say you have 1 ppb of lead in your tap water. You add Prime _to
> the tap water_ and the Prime removes the 1 ppb of lead.
I can see it would reduce the free lead concentration to
an even lower (but non-zero) value, but if you don't remove the
complex, it will still be there. Removing it will not be easy,
because even if its formal solubility is very low indeed, it will
be in the form of extremely small particles.
> You then take
> that tap water and add whatever you normally add to it in preparation
> for doing a water change. Nothing else is lost because the trace
> heavy metals in the tap have already been removed.
To where? Physical removal will be necessary, if you don't
want the iron, manganese, etc., to displace the lead from the complex
by dint of much higher concentrations.
> The effect is very
> minor and operates in the sub 10 ppb range. Also, the "heaviest" of
> the heavy metals are preferentially precipitated (i.e. leady,
> mercury, cadmium, etc).
Agreed, but they can be displaced even from the solid by other
metals if those other metals are at higher concentrations.
In practice, I don't worry about true heavy metals (lead, etc.),
because I reckon they will be adsorbed on all the finely divided material
that exists in the aquarium and in the filter. I don't have chlorine
or chloramine in my (well) water, so I skip the whole "water conditioner"
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