The local stuff is *not* Bomix - it's just something I dug up and is potentially useful but very possibly not. Bomix is mostly available back east, and I've heard of it as far east as Calgary. Still nothing in BC from what I saw.
Southdown is only available back east because it's mined in the Caribbean and carted over to Florida for distribution. It would be ridiculously wasteful to have a single point distribute millions of tons of play sand across all North America. End result is our play sand here isn't aragonite but it's produced locally and costs far less to transfer. You'll probably find nearly all of the sands/cements in the local hardware stores are from Target Minerals - they're based in the Lower Mainland (or if nothing help have large offices here) and do their mining in BC.
It would be really nice to have the Southdown stocked everywhere, but if I were a reefer and the head of Home Depot, I still wouldn't do it.
