I bought 2 gallons of the Zerex G10 concentrate. I'll use distilled water with it. I have no clue what was in it before. Probably some orange stuff, but you couldn't tell with that sealer crap in it. It seems to be holding at 175 now and gets there faster than it did with no pressure on the system. The tractor actually seems to run better. I can't wait go get back out to the south field in this heat. I did 2 smaller fields the other day that I never got to last year it was so wet. There were days last year I could really not take the tractor out in the fields, it would just dig up mud.