Coolant causing sputtering torch

If you have been following my sputtering torch thread here is the end of it.
Took out the auto antifreeze and put in distiller water . What do you know my sputter on AC is gone and the torch starts smoother. This was driving me crazy. I can now ramp down to 5amps and still have a steady non sputtering arc. I read somewhere that this could cause hf problems. Made sense that AC welding is basically hf welding. And dc is straight. Hf start on dc have cleaned up tremendously as well.