Dishwasher problems. Hi. I have been having issues with my dishwasher the last month or so.

Question

Hi. I have been having issues with my dishwasher the last month or so. There is a white powder-like residue left on dishes. I noticed it most on my silverware. At first I thought the detergent didn't rinse off completely so I did a ran it again without any detergent a couple of times. Still there. I bought some stuff that is supposed to remove build up from hard water. did that twice. Increased the amount in the rinse aid dispenser. Now I have noticed that the drying coil? is covered in a white "powder" as well. I can wipe it off with my finger. What could this be?