after buying the wrong de at one feed store who adamently claimed it was 'food grade' de (85% silicon dioxide), i went to another feed store and worked with the manager to get the right de. i had him go to BYC home page and simply type de on the search line at the bottom of the page. i had him follow the links from dawn419 about the right de and he contacted his supplier to get the REAL (food chemical codex grade) de for us. once he saw the info, he was more than happy to help and i didn't have to try to convince him that i knew what i was talking about (he knew i was new to chicks). the store was Waldens in weatherford, tx and i think we will have a long business relationship. my thanks to Clark the manager at Waldens for all his help. maybe others could try this at their local feed store. thanks,rich