Rinse aid remains on the dishes in the form of stains. On Teflon, water collects in drops, and this is clearly visible. On ordinary dishes, thanks to the rinse aid, the water spreads evenly in a thin film over the surface, and such residues are not visible.
The water could become harder if the intake was taken from another place or the hydrological regime of the reservoir or underground source changed. Or changed the brand of salt used in the dishwasher. Or it just ended.
We recommend changing the rinse aid flow in one direction or another. We changed it to a step, looked at the result. Not satisfied - have changed. And if the maximum consumption does not ensure the cleanliness of the dishes, then call the master. If you need help with dishwasher repair, call us right now!