Re: K2O, KCl

P Krombholz writes: 
>You can also get potassium alone as a fertilizer at some gardening stores.
>This, however, is mostly potassium oxide, rather than potassium chloride.
>I vaguely recall that Neil Frank is using this as his source of potassium.
>Am I right, Neil?  If so, how is it working?

Muriate of Potash is sold in the garden and hardware store. It's ingredients
are listed as Potassium Oxide (K2O). Apparently, this is the convention for
listing the 3rd macro nutrient contained in all fertilizers. Muriate of
potash is another name for Potassium Chloride (KCl). The ag grade KCl has
some contaminants. I understand them to be NaCl. Whatever they may be, it
has never hurt any of my fish or plants. I had been using 1/4 teaspoon per
70 gallons of water with a biweekly 20%water change. This results in an
additional 2ppm of potassium. (Now I use KNO3, because my tanks are nitrogen

Neil Frank, TAG editor    Aquatic Gardeners Association    Raleigh, NC USA