Umm isnt that what they use for plant mix at the stores? If so i wouldnt use it ... since cacti like to dry out between watering it dries up and forms a block that doesnt absorb and more water and it just washes by it ... and then your cactus never recieves water again ...

Or maybe im Thinking of peat ... but heres a link to a similar post ...

Here is a link that might be useful: other post

I have used perlite and vermiculite for many years. I prefer large grain perlite, as vermiculite can have various effects on soil pH. I do not use more than say 20% if I use it. It does help with aeration insulation, but degrades quicker than perlite I believe. Here is a link that would require some reading, but there is lots of info.

Here is a link that might be useful: Perlite & vermiculite

Woah beach where do you even start on that o_o

Very informative link, Rian. I've been told that vermiculite is a fine addition to soil when used as Rian suggested. I don't use it only because it's much more expensive than other materials available.
Many of us mix our own soil and everyone does it a little differently. You can try to follow the 'gritty mix' guidelines but I haven't been able to acquire all the ingredients.
What I do is to sift all the fines out of each of my components with a large wire strainer. I start with either bagged cactus soil or regular potting soil. I add volcanic pumice and Napa oil absorbent, together making up about 50%. After sifting our all the fines, this mix is a little too gritty, a little rough in my opinion. I like to add fines back into the mix in the form of coco peat which does not become hydrophobic. I don't add much, but enough to add some buffer between all the sharp grit. I don't really measure anything, just shoot for a certain texture.

I think at Uline the Vermiculite is not too expensive. Because such a 4 cu. ft. bag makes a lot of soil mix.

Jordi

Here is a link that might be useful: Vermiculite

Thanks Jordi! I have their catalog!