As you are finding out through the school of hard knocks, carwash chemistry is more a science than an art.
Anyone in the chemical side of this business who is worth their salt should want a tap water analysis and then be willing to come to your site and spend a day with you to help set up the delivery system and calibrate the carwash processes to achieve the best possible finished product and cost/car.
If you are dealing with a regional brand or worse, a bathtub blender, that is content to sell on the basis of low price, drop ship chemistry and telephone support, getting the right combination of performance and cost might be as difficult as trying to hit a moving target while wearing a blindfold.
For example, you have been open only 7 months and you said the quality of the in-bay still sucks. It probably also sucks for your customers.