We have used alot of coolant types over the years, synthetic, water soluble...ect. We have had coolant that burned the eyes, caused dematitis, caused boils and alot of other nasty stuff. We have currently started to use cimperial 1070 and made the switch from cimtech500. We found the synthetics have a alkaline ph and will etch aluminum parts before any kind of plating. cimperial 1070 gives us better tool life and even though we have to watch it closer (may grow bacteria) it seems to be more pleasant in odor and the nice blue color makes it alot funner to use....can you even mention fun and a machiner shop in the same sentence.....Hell yeah
What are you using and what is your story