I understand hat your saying. Not sure who your talking to though. I was gonna buy a unit and make my own but since a good friend almost like family has owned a mom and pop shop for years I use his water, the same water he uses for his tanks. I'm confident using his water and after 9 months of using his water have never had an issue.
If he ever stops making the water or there's an issue then I'll reconsider.
"When creating an aqua scape, strive for the beauty of imperfection, as its art and there is no wrong or right, it's left open for interpretation" James Findley