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Re: Chemistry Questions: N-P-K Ratios

  George wrote:
  (NH4)H2(PO4)  N = 12.18%,  P = 26.93%
  (NH4)2H(PO4)   N = 21.21%,  P = 23.48%
  K2HPO4   K = 44.89%,   P = 17.79%
  KH2PO4   K = 28.73%,   P = 22.76%
  Ca(H2PO4)2  (superphosphate)  P = 26.47%
  CaHPO4    P = 22.77%
  Ca3(PO4)2  P = 19.97

George -

Thank you, this is getting toward what I was wanting to know.  I assume these
percentages are by mass?  What would be the equivalent percentages of N and K
in KNO3 and K2SO4?  It looks like K2HPO4 starts out with the lowest amount of
P.  If I measured out the right proportions of that, and then added the
appropriate amounts of KNO3 and K2SO4, based on these percentages, can I mix a
solution with a known N-P-K ratio?  I'm planning on using a huge hypodermic
syringe to inject this deep into the substrate where, theoretically, the
cation exchange sites in the clays and vermiculite I've added will hold these
nutrients out of the water column.  That's the experiment anyway....Is there a
reason already known why this won't work?