AdBlue should meet the DIN V 70070 standard and ISO 22241-1 specifications and complies with ISO and CEFIC regulations to safeguard the correct functioning of your vehicle's SCR system. The product is slightly alkaline with a pH of approximately 9.0 so should not be kept in contact with aluminum, brass, mild steel. Stainless steel and plastic tanks and fittings are recommended. Freezing of AdBlue starts at minus 11.5 °C AdBlue can be used once it has frozen. Once AdBlue has melted, it can be used without problems. The best way to remove crystallisation or spillage is to rinse with water. When you rinse with water be sure that the is well sealed in order to prevent any contamination of the dilution.