Re: ethylene glycol vs propylene glycol freeze protection
I personally don't use the testers sold at automotive parts stores. I perfer a refractometer. Which has a scale on the display for both types of antifreeze as well as a scale for battery acid.
Here is one for sale on ebay for around $20.00 plus shipping:
http://cgi.ebay.com/Battery-Acid-An...468?pt=LH_DefaultDomain_0&hash=item4cf22837b4
In the heating business, sometimes we have to add antifreeze to heating systems depending on the system design. The refractometer is the tester we use to check the strenght of the mix.
You put a couple of drops of the mix on the glass, and hold the refractometer up to light while looking thru it.
When you look thru the eye piece, you see the round scale in the picture, the strenght of the mix will create a line across the scale, blue on the top and white on the bottom, where that line intersects the scale is the strenght of the mix.
They also sell them for testing strenght of sugar in fruit in wine making and alcohol.
