Lime scale Bits left on glassess and cups??

I have a Hotpoint Aquarius DF61 model that is approx 11 years old (so ive had my moneys worth out of it really) - it still in good working order except that ive noticed the glasses and sometimes cups are left with a residue that appears to be like tiny pieces of lime scale? ive put numerous cleaning agents through the machine to clear it out (with well known products) but it doesnt make any difference - why is this? and what can I do about it? the dishwashers still going great and I dont want to spend unnecessary money out on a new one if something can be done??

omedarling
January 2010