I have a couple chemicals that are clumping up pretty badly, mainly because they were technical grade and ground with a coffee grinder. I have two chemicals which I believe are anti-cake agents: Cab-O-Sil and Magnesium Oxide.

I've looked around the forum and have seen many references to them, but no information about how much to use. I've heard 1%, but is that by weight or volume? I assume by weight, but I ask because I have 1179g of Sulfur, and 11.8g of Cab-O-Sil is an awful lot. Or, if I choose to use MgO, how much would I use? I'm not using it in flash or anything, I just want to keep the chemicals free-flowing.

I personally hate anti cake agents, why contaminate your valuable reagents?

That aside, the recommended use is .30% - .70% (I assume its by volume seeing as its density is so low, my literature doesn't state) cab-o-sil.

Aren't ACA inert? I figured that's why only certain ones are used.

Depends what you want to do with them, nothing worse than trying to make a solution with something only to have a thick scum of anti cake on the surface.