Join Date: Jan 2008
I am not familiar with that particular brand of water softener salt, but if it is purely potassium chloride, then it should be fine for use.
You want to make sure that it is potassium chloride and not (the more common water softener salt) sodium chloride nor a mix.
In terms of concentration, water softener salt is probably technical grade, which might have a few impurities, but should generally be fine.
You might be able to find an agricultural farm that sells agricultural grade (which would be a little purer).