Here is a shot of a better true propylene glycol antifreeze product safe for most plumbing parts. It also has a decent corrosion inhibitor. It is safe for engines and domestic plumbing systems. It has no alcohol in it.


The item in front is a sight refractometer. This is a tool I use to test the concentration of teh AF in the system to determine when I have pumped enough through the system. Samples are taken at each faucet, shower head and wash-down spigot etc...


Star Brite Aintigel -50 is also an excellent -50F product. If you are in an area that gets really cold, less than -25F then you may want to consider a -100F rated product.