I just went back and re-read the article this morning just to double check some thing. While there I noticed this warning about the Dead Sea Works Mag Flake.
Editors note (3/10/07): Note, the manufacturer of MAG flake has alerted us that they very strongly recommend against using this product in reef aquaria. While many reef aquarists have successfully used the product, the manufacturer does not claim to be able to provide this product at suitable quality in the future.
I just thought it would be useful to spread this around.