This isn't really a Calgary-specific recommendation, but after going down this rabbit hole myself a couple months ago, I eventually bought CaribSea (brand) "Peace River" (blend name) sand/gravel from a local aquarium store. It's quartz, and spec'ed at 1.0 - 2.0 mm in diameter, which puts it somewhere between #10 and #18 grading (so I'm not sure if it should be classed as a sand or as a gravel..). It seems to be available in different places online, but I couldn't find an easy way to get it delivered quickly without paying for shipping, so I went on a physical tour of local aquarium stores here around Vancouver until I found somewhere that had it in stock. And then once I found it, I realized that that store actually offered a few different options from different brands in that same size range, and I was suddenly overwhelmed by the options! I still ended up getting a 20 lb bag of the CaribSea "Peace River" I'd been originally looking for because I thought it was the prettiest, but I spent entirely too much time making that decision.
I'm pretty happy with it so far, but I've only been using it for a couple of months.