Correct process would be snowfoam before you powerwash the car, it dwells better on a dry car. Foam, let it dwell while you wash the wheels, blast off, another coat of snow foam, wash with lambswool mitts, at least two mitts maybe three, blast off preferably with de-ionised water, then use an open hose on a slow foam to sheet the water off still using your filtered water. Dry off using plush drying towels, again 2 or 3 for the different areas. That's the weekly process. Occasionally polish, wax and seal to keep it all sweet.