Stop using the Multi Tablets
Ensure it has Salt
Ensure you use a good quality powder
And above all ensure you use a good quality liquid rinse aid.
Rinse off the worst of the food debris from your cutlery and crockery before loading it into the machine.
Why?
The rinse water will contain the food stuff you put into the machine but broken down into fine particles - the rinse aid chemical helps the rinse water to drain off.
If the rinse water does not properly drain off the dishes the drying process just bakes on the food particles to leave things dirty.
Clean the filters now and again - annually perhaps.
Liquid rinse aid - always keep it topped up.
Reduce the amount of solid food you load into the machine.
Any dirt you see will be what you put in.
Good Luck...
October 2015