I have very hard water and have a water softener that creates very soft water. This is apparently a rare problem. The water is so "soft" that sodium water spots are created when I wash the car. My question is, what do I do to get rid of the sodium from the water (short of getting another reverse osmosis system just for car washing)? In the future, I'd like to use Meguiars QD or Griot's Spray on, or something like that, but I have some small sand on the car that I need to remove with water. Thank you for the input.