Our solution is designed not to leave any residue or coating behind after you rinse it. It is actually not a good idea to coat the coils with any coating after cleaning. Reason being, you can potentially modify the surface energy of the cooling coils thus speeding up the rate at which organics (skin flakes) and dust particles to cling to the surfaces which in turn act as food source for bacteria and mould. This is the reason why air conditioner engineers have put in a hydrophilic (repel adhesives) coating on the coils in the newer systems.
The way our solution works is it turns any surface it touches hydrophilic thus repelling any adhesive that is on it almost instantly. This then allows the organics (skin flakes), biofilm, and dirt to be washed away by the rinsing and flushing with water.
Currently conventional cleaning solution attacks and erodes the oxide layer of the aluminum to remove the biofilm. That is why you see a shiny coating after wash. The downside of this method is this strip-mines the aluminum material off the cooling fins. There is a limit to how frequent one can use this method on an air conditioner. Plus, if you happen to leave some cleaning solution in the system, it will continue to corrode any metal it stays on.
Note: Hydrophilic coatings create low surface energy which repels anything that wants to stick to it. Hence, they reduce the rate of organic build up and allow the condensate to flow smoothly over their surfaces. This means the condensate will drain effectively and not contribute to blocking the airflow and reducing the air conditioner efficiency.