The newer 'Green' Mineral replacement is just mixed with water and will settle out over time. That water will go to the bottom of your washer tank and mix with the crud. NASTY.
Funny you should mention this because a couple gallons of water is not a bad thing as long as its below the pump pickup. Firstly, the water and solvent don't mix so the water settles. Now all the crud settles in water instead of solvent - water is free!. There is no disturbance in the drum to stir things up so the crud stays in the bottom keeping the solvent cleaner. The water raises the level of your solvent thus giving you that much more to work with. It might take a while for the water to settle out of solvent but it would settle quickly if you're using diesel fuel.
You guys using gas of any sort ... what do you heat your shops with ? I wouldn't personally use gas in a shop unless it has electric heat and even then there are many other things that cause sparks - startup on my compressor, sparks from grinders, the welder, etc, etc.
