I have a serioud Dishue

When ry and i first moved into our home our dishwasher crapped out and our landlord got a nice new one for us. It has been 6 years, and the thing is crapping out. It still washes (sort of) and it still dries (most of the stuff) but for the last little while it has been leaving behind bits of something behind, which kind of looks like sand. (i shall refer to this concoction as the 'Shit AGAIN Needs Dishwashing' or S.A.N.D. The weird part is, the S.A.N.D. only ends up inside the glasses on the top shelf, and only in certain glasses. The glasses are different shapes, so it's not like i can get rid of the glasses that the S.A.N.D. is attracted to... unless we want to start drinking out of beer cups again. Previously, when the S.A.N.D. infected our glasses, a second run through the dishwasher cleaned it out, and all was well with the world. Not this week. I have run the same 10 glasses through the dishwasher at least 3 times to no avail. we even removed all the dishes, and the racks and ran the dishwasher on its own - one round with vinegar, one round with tang, one round with regular soap and one round of just hot, hot water. we also checked the food traps and gaskets, which are all clean. WTF?!??! due to the time invested in running so many loads (sorry environment) our dishes have been piling up. last night we had no counterspace, no big plates, no little forks, no bigger (more than 1 litre) mixing bowls, no square pyrex's, no big frying pans, and no sanity.
*sigh*
I guess it is time i got out the dish gloves and washed the glasses by hand... boo-urns.

*disclaimer* for those who use the glasses in our home, please rest assured that we check each glass before putting it away. There should be no worries that you are drinking out of a glass that is contaminated with S.A.N.D.