- I typically use RealSalt which has a bunch of minerals in it. That's what you're seeing. It's a super-raw salt dug out of the Utah desert. I like the nutritional philosophy behind it, but the truth is, it leaves a bunch of grit behind that doesn't dissolve, and sometimes that's not what you want. :-)
- I do a whole lot of my fermenting in Fido brand jars by the Italian glass company Bormioli Rocco. They have a rubber gasket that acts very much like an airlock and are quite inexpensive. The metal wire that makes up the 'bail-top' mechanism does degrade over time -- gets sort of rough and corroded with washings, but I've been using them for something like seven years and none have actually failed yet, so it isn't too bad. I like the fact that I get the benefits of a water-based airlock, without the overhead space being taken up. That's useful on shelves or in the fridge.
2a) There is also a whole slew of products that bring a gasket-style airlock to canning jars. I have one set of Easy Fermenter lids that work quite well, though I can't say for sure that they're better than any other similar product on the market. (A side benefit of these Easy Fermenters, is that the canning jars then stack, so if you're using the short-fat pint jars, you can pile them up on the shelves while your produce ages. - The batch of Oi Sobagi that I made was too large to all fit in that 3-liter jar when I was first packing it. So I left some in a tupperwareish thing. The next day, when I was plating up my entry, the cukes in the jar had all shrunk and produced a bunch of extra brine. So I plated the above dish from the plastic tub and then was able to shove all that was left into the jar, pressing down, which causes the brine level to rise and mix with the veggie-pepper paste, helping to preserve the fermenting produce and also spread flavors. I didn't add any extra brine. (Keeping fermenting produce covered in brine is one of the laws that many, many people follow dogmatically, but I've found in these gasket-topped jars, so long as I'm not opening and reclosing them, the headspace becomes all CO2 and prevents any pathogens from prospering -- so I'm not as anal about it as I am with an open-top ferment, which I also do.)
I can talk your ear off about fermenting! :P