I got confused and thought the pic posted by Sue was a picture of Lynn's, and I noticed a pad just below the 3 o'clock postition that looked like it had some of the residue Lynn posted about. I now know I was wrong about the pic and who posted it.
But, will still under that delusion, I went out and found a few pads that had something on them that looked like what I saw in the picture and took a sample of it. Under the microscope, at all three magnifications (40X, 100X, and 400X,) the sample looked the same, like rather non-descript little grains of sand. Not actually like real crystal formations, just irregular shapes, and definitely NO legs!
My well water is typical for the area I live in. It is hard, about 330 ppm, last time I tested it. Hard enough to leave a white coating on glass, not quite hard enough to plow.
In my case, anyway, I'm pretty sure that the residue that worried me a while back was nothing more that what was left of water sitting on the pads, after it had evaporated.
Mike S.
Spring Hill, FL