You might like to read this thread, it will also bring you
to several good links. You can also do a search on DE in All Forums.
The way you use the DE here is, put a tbs in a gallon of
water and let it sit. You drink the water and keep adding water it will lasts for as long as you want. I usually start from scratch every 6 months. Just buy a bottle of distilled water and add DE. You can read for more explanation in the thread.