Some times The customer wants to see where leak is. I live in the show me state. found multiple leaks with bubbles and detek. when leak is in middle of coil
with dye in system you will have a scenic view for customer to see. Boss bought these new kits and ultra violet light you carry around. It used to be a big light in box you had to retrieve it from shop to use. When you have windy conditions, it is ALMOST impossible to find leaks with sniffers, you need device to hear it or see it