I have a GE 10 year old dishwasher. Lately there is a film and sometimes grit on the dishes. I always rinse the dishes but I don't wipe them off. It has a built in heater to raise the temperature of the water, but GE suggested I increase the temperature at the hot water heater. It now reads 125 degrees. There is no filter, but we took the covers off the two areas on the bottom and cleaned out a little gunk that was on the sides . I tried running ascorbic acid through without dishes.

The motor works fine. I peeked inside and the spray arm works okay. Any other suggestions or is it time for a new one?