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Re: RO recon

> One set of comments down.  Any other?

I found that the bulk density of powdered chemicals such as CaCO3 can
vary quite a bit. This was especially true for the chelated trace
elements which we have been getting here in Vancouver (from the same
source I believe). They have changed the formulation and the new powder
is about twice the density.

You will have an error in calculating concentrations when using
volumetric measures such as teaspoons and cups, however the target
concentrations are not at all critical. According to Paul, it makes
virtualy no difference if say the potassium concentration is 5ppm or 100
ppm so long as there is a sufficiency. What that means is that you
should dose to a high enough level that the nutrient does not end up
being used up. Obviously for iron, there are other reasons for being
concerned about the actual concentration since this nutrient and
phosphorus should be the growth limiting nutrients in solution in order
to restrict algae.

To summarize: its ok to use tsps to measure CaCO3, potassium and
magnesium salts but you should _probably_ use an accurate scale for
measuring chelated trace nutrient powders.

On other thought occurs to me: the bulk CaCO3 seems to be harder to
dissolve than the finely powdered stuff I bought from a pharmacy. I
think there's a difference in texture (particle size).

Steve Pushak                              Vancouver, BC, CANADA 

Visit "Steve's Aquatic Page"      http://home.infinet.net/teban/
 for LOTS of pics, tips and links for aquatic gardening!!!