Thanks for the advice. Actually, since I posted this, I checked my fermenter. The bottom is quite clear. Most of the stuff on the sides is gone, but that might require a bit more effort. Apparently, phosphoric acid works.
Recently, after having let my 6 gal. glass carboy soak overnight in bleach-water, I found quite a lot of sediment at the bottom (and a good deal on the sides). A friend of mine suggested that it was hard-water calcification.
I have been unable to remove this sediment. I have used 1-Step...