ANY Diatom Powder will be OK, if you check to be sure it has no additives, such as chlorine producing compounds, etc. "Diatoms is Diatoms." <ggggg> Personally, I am using about twenty pounds of Swimming Pool stuff that has no additives. At the rate I use it, I have a "Lifetime Supply!" Cheers! JOlson8590 at AOL_com Out in the Boonies, near Cambridge, Iowa