Gritty residue in dishwasher

[Montifer]

This has started appearing mainly inside mugs on top shelf, anyone know why?

Should I be doing some dishwasher maintenance other than emptying the filter now and again?

TIA

the rotor arms may be blocked - you should be able to remove and clean them. You could also run a cycle with the machine empty and a cleaning tablet/liquid.

Deffo the rotar arms. i had the same

Thanks, have cleaned rotor arm, didn't seem to be blocked or dirty, will see how next wash goes.

it was something else in ours that caused this. i can't remember what it was called but i think it meant the water didn't heat up. the dishwasher man had to fix it by replacing hte part.