Pszemol wrote:

Unless the water used in both tests is different, of course.

He said he's using RO generated from creek water. The creek water at least will
be different from day to day and maybe from hour to hour. If somebody fertilized
upstream on that day, the RO filter will have to work real hard to get all the
phosphates out.

Anytime you make a claim about phosphates or nitrates, you HAVE to test the
source water before mixing in the salt. If you don't, your tests are inconclusive.

George Patterson
Coffee is only a way of stealing time that should by rights belong to
your slightly older self.