I'd be careful using distilled water in your compressors, although it is free of the minerals that could cause the formation of scale, because of its purity it becomes aggressive to metals and causes erosion. The best choice for these compressors would be to run soft water in the cooling systems, it will be free of the calcium and magnesium that would form scale, but it's not corrosive the way that distilled water is. 30 years in the water treatment industry if that explains anything. People often don't realize that water is a universal solvent, that's how it becomes saturated with everything it comes in contact with, the purer you make it, the more it wants to dissolve anything it touches.
Good catch David, I ment to mention those as well but got focused on the distilled topic. That's the very reason why R0 units use plastic fittings and tubing.
Again off topic but at the same time, your body cannot absorb, burn or process the minerals it takes in through drinking hard water, they are in the wrong form and must first be converted by vegetable matter to be usable. Whatever raw minerals your body takes in that are unusable must be flushed out through your kidneys and your urine, whatever it can't flush out gets parked in the body in the form of ostio-arthritis, stones, cataracts, etc. Information written by a medical Dr. in a booklet titled The Choice Is Clear, which recommends drinking water in its purest form in order to flush unusable mineral buildup from your body.
I remember a fella at work that had a whole house Di system. He was constantly buying bottled water to drink. He said he couldn't drink the Di water, that it lacked needed minerals and such. It didn't make good sense to me to go to that expense, but he did mention something about his wife's issues with drinking water and health issues?
Thanks for the additional information David, Things and information are always evolving by newer science and information. Haven't really done any water treatment since leaving Florida 16 years ago. Spent 30 years in water treatment between Indiana and Florida but have been The Home Depot Nashville plumbing pro since moving here then. Don't get to read all the industry magazines I did back then to stay abreast of what's happening. Still try to steer my customers away from a lot of the snake-oil peddlers out there though as the public is largely ignorant, and there's always someone willing to take advantage of them. I'm not afraid of learning something new however. Hope we're cool.