Why specifically FOOD GRADE diatomaceous earth??

[Amyable]

As I understand it, pool grade DE is heat-treated, which changes the composition of the silica. Food grade DE is not heat-treated.

 

[ivan3]

amyable wrote: As I understand it, pool grade DE is heat-treated, which changes the composition of the silica. Food grade DE is not heat-treated.

And melting/cooling SiO2 produces what amounts to minute shards of glass (apparently the 20% crystalline DE is useful in preventing the remaining 80% of the DE from gunking up when using as a filtering agent in pools). Not something to be spreading in the hen house.

ADE kills insects, primarily, by adsoprtion - not friction (mechanism of action continues after insect is dead - no movement/no friction - it doesn't desiccate the insect by `cutting' it up)​