I have been thinking about using DE in my chicken coops. I found some at our local aquarium and pet store. The manager did not know if it was food grade or not. They have it to use in certain fish filtration systems. Would it be safe to use mixed in with the shavings of the coops? I'm hoping so. It was only $5.99 for a fairly good sized bag. If not, where can I find it? The health food store has food grade, but it's $13.00 for just a pound of it!!!! thanks for any help anyone can give me.