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Re: potassium levels/water softener

On Fri, 12 Jan 2001, Ron Barter wrote:

>     I thought I would use potassium rather than sodium in the softener,
> which leads to my first question: will the water, after going through the
> softener, contain the same concentration of potassium as it now does calcium
> and magnesium? In other words, will I end up with water containing 329 ppm
> of potasssium coming out of my hot water tap?

Wow, you can do that?  Depending on the efficiency of your softener, the
potassium content in your softened water could increase by about 660
mg/l, and the net increase in total dissolved solids is 331 mg/l.
If you use sodium the maximum rise in the sodium content is about 390 mg/l
and the net increase in total dissolved solids is only 61 mg/l.  I suspect
that you would taste the difference.

>     If the above is the case, then after mixing my hot and cold water at
> a ratio of 3:7 to get the temperature I want, I'll end up with a
> theoretical 98.7 ppm K (and 219.1 ppm calcium and 11.2 ppm magnesium)
> I'm assuming that I can probably eliminate the potassium sulphate from
> my PMDD <g>, but will this level of K cause a problem? Block uptake of
> other nutrients? Toxic for fish?

Hydroponics literature cautions strongly against large imbalances because
it causes symptoms of deficiency in whatever is proportionally low.  I
don't know how big the imbalance has to be before potassium causes
problems. From my experience I think that sodium causes problems when the
Na:Ca+Mg ratio gets close to about 20.  I suspect that you could take
potassium up to higher proportions (say 50 or more) so you may not have a
problem (well, at least not *that* problem), but at some point
there will be problems.

Some plants are more sensitive than others.

Roger Miller