dyeing glycol for leak detection

[NateC]

What do you all use to dye your glycol for leak detection? Any reason regular food coloring won't work?

[TGTimm]

Nope. It takes quite a bit (don't recall just how much), and some colors will stain your lines and some will not last. I'm sorry, but it's been too long to remember what I used. Best thing is to contact your glycol provider and ask what they recommend.