Step 7: Sucking The Antifreeze Through The Water System:
With the hose full of antifreeze and the pump primed, use a clean bucket, or the hose stuffed into a gallon of antifreeze you are now ready to flip the switch.
Turn the water pump switch on and open each tap, in rotation, until it runs a color that looks the identical color in the bottle.
Run and test each tap until the concentration of the PG matches exactly what is in the new bottle. If you don't have a refractomer samples in a clear wine class placed next to a new undiluted sample can give somewhat decent guidance. When in doubt suck in more!!
Another gallon or two will ALWAYS be less costly than a freeze up!!