Proline Logic Dishwasher never cleans properly ?

Proline Logic Dishwasher never cleans properly.

1 I have changed the Salt
2 Cleaned the filters inside
3 Made sure its toped up with rinse aid

Still, after it has finished The Dishes come out and with a finger you can wipe the chalkly scum off of everything I have put in. No its not a hard water area problem , It used to wash fine.

I have tried as Proline suggest to wash empty a use a couple of pints of vinegar. Even tried Harpic Toilet cleaner all to no avail, Please tell me whats wrog with it.