Speaking of the Speedstir, jsalz, if you don't have one, it makes the salt test hundreds of times easier, and that's no exaggeration. If you haven't done the salt test yet, the sample gets very thick with particulates in it. So thick that the SpeedStir even has trouble stirring it if the batteries are even remotely low (like under 50%). Its even harder to get a decent stir when you are swooshing it by hand. Not saying it's impossible to get an accurate result without it, it's just so much easier. When I test my water tomorrow, I'll take a video of the SpeedStir stirring this test.