A working solution is the ready-to-use mixture created by diluting a car wash concentrate with water at the specified dilution ratio. It is what actually contacts the vehicle surface during washing. The properties of the working solution — not the concentrate — determine cleaning performance, surface safety, and cost per wash.
Key properties to control:
- Concentration — measured with a refractometer. Too low means poor cleaning; too high wastes product and may damage surfaces.
- pH — check with a pH meter. The working solution pH is significantly lower than the concentrate pH due to dilution.
- Temperature — warmer solutions clean better. In winter, pre-heating water can restore performance lost to low ambient temperatures.
Preparation methods:
- Inline dosing — a dosing pump mixes concentrate into the water stream in real time. Most consistent and recommended for professional operations.
- Batch mixing — concentrate is manually measured into a tank of water. Common in detailing and small operations. Requires careful measurement.
When using Fortis Foam PRO at the recommended 1:50 ratio, the working solution has an optimal pH for touchless washing and sufficient surfactant concentration for thick foam generation. For detailed preparation guidelines, see how to choose active foam.