I use Spiralite 170, milk hose. I get it from Eastern Crown Inc. in Vernon, NY. It is food grade and rated from -10 to +130 F. They sell it by the foot and the price is good. Fast shipping too, same day if you order before noon. Likely other dairy supply vendors sell it too.
Dave Klish, I recently bought a 2x6 wood fired evaporator from A&A Sheet Metal which I will be converting to oil fired
Now have solar, 2x6 finish pan, 5 bank 7x7 filter press, large water jacketed bottler, and tankless water heater.
Recently bought another Gingerich RO, this one was a 125, but a second membrane was added thus is a 250, like I had.
After running a 2x3, a 2x6, 3x8 tapping from 79 taps up to 1320 all woodfired, now I'm going to a 2x6 oil fired and a 200-425 taps.