On Sep 25, 2:05*pm, Paul > wrote:
> I am going to premix 1.5 tsp of potassium metabisulphite with 24 oz. water for a spray bottle. How long will the solution stay active? Is there a shelf life in solution form?

You need to acidify the solution also, my normal ratio is 1/2
teaspoon K2SO4 to 1 teaspoon citric acid per 32 ounce spray bottle.
I've had it around for several months.

Joe