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Re: Seachem Phosphate

Kevin writes:

>   I am playing around with 2 new testing kits, Seachem's iron and
>  phosphate (thanks to all who forwarded me instructions for the latter).  
>  phosphate indicates that the levels in my tapwater are about 1.5 ppm.  This
>  seems ridiculously (dangerously?) high.  I have a City of Detroit Lab
>  Analysis Report from '98 claiming tap water levels of phophorus to be
>  0.29-0.31 mg/L.  How do phosphorus concentrations relate to phophate, is
>  this excessively high, and what can I do to remove it without using RO to
>  strip out everything and then rebuild?<snip>>

Phosphorus has an atomic weight of 31.  Oxygen has an atomic weight of 16.  
So the PO4- ion has a wieght of 95.  A test result of .3 mg/l P is roughly 
equivalent to a result of .93 mg/l PO4.  Since mg/l and ppm are pretty much 
the same thing in fresh water, you are looking at a discrepancy of almost 
.6ppm.  I'm not going to guess which one is right, but there may be seasonal 
fluctuations, which means the time of year that the test was taken has an 
affect on the accuracy of your tapwater analysis today.  As for getting rid 
of it, I wouldn't bother unless you can determine that it is actually causing 
a problem.  There is a product available at the LFS called Phos-sorb, which 
will adsorb the phosphate out.  It's kinda spendy, though.

Bob Dixon