Have new dishwasher but it does same thing old one did. doesn't clean, leaves film on dishes, esp. glass.?

Just bought a new dishwasher because old one didn’t get dishes clean and left film on dishes, especially glass. But new one does the same. We have hard water, just manages to be drinkable. I Live in a small town. We have a water softener and a filter hooked up. Repairman says he can’t find anything wrong with the dishwasher. Does anyone have any idea what else it could be to cause this? Thanks for any advice.