Our feed store only had the "toxic" stuff, which I realized after they tried to sell it to me as food grade and I asked to see the ingredients. Most are not aware of the differences. We get ours from McGeary Organics in Lancaster, PA. They ship it right to our door. We order 50 lb bag for about $50 (inc. s/h) and it lasts about a year. Any local organic places should carry it.
Jody
Jody