I am losing ~1/4" of water per day, and it appears that I am losing it while my pump is on through the multiport valve waste port. I can see a trickle of water (especially when bubbles are present) through the clear inspection piping.

My multiport valve is a PacFab 8 position unit that is 11 years old - see http://www.eatel.net/~vgg659/PacfabValve.JPG .

Should I replace or rebuild the valve? If rebuild, is it hard to do and where can I find a kit?