Pressure gauge indications:
White colour range indicates that the system pressure is too low (less than 25 psi).
You should add refrigerant to the system until the gauge indicator is in the green range.
It is always recommend to use sealant first and then refill the system with gas.
Green colour range indicates the normal and recommended A/C system operating pressure (between 25 and 55 psi).
The level of gas in the system is correct. If pressure drops (the indicator moves to the white range), it is recommended to use the LeakStop sealant.
Red colour range indicates that the system pressure is too high (above 55 psi).
In this case, it is recommended to decrease system pressure.