Angelus666 said:So, with these it’s best used for the rinsing part of the clean. So do your wheels and pre clean with normal water, then add the DI and do a rinse. Then you can shampoo the car without chasing water spots. When you’ve finished that, then rinse with the the DI water. This should keep you water spot free and an 11L will last a good 50 washes. You’ll know when you need to change the resin when the car starts to water spot.