Thommas,
I think R/O water works fine. I use it to clean my records. I would bet that most other forms of demineralized water would work fine too (distilled, cation/anion exchange that is not based or replacing water hardening minerals with salt).
I just think that the steam cleaning method is a big hassle compared to wet cleaning and vacuuming. I hardly ever find a used record that does not clean up by using such machines, and I never let my own records get terribly dirty. I have the same Nitty Gritty machine for almost twenty years and it does a good job and is easy to use. I don't use the automatic fluid dispensing feature (I apply fluid from a squirt bottle) and I don't even use the rubber wheel to turn the record (I prefer to turn by hand so I can scrub back and forth). Thus, for me, the cheapest machine would be enough. The idea of having to get out a steam cleaner, fill it with water, wait for it to heat up, clean the record, dry the record, empty the steamer, etc. is just too much trouble for regular, every day use.
I think R/O water works fine. I use it to clean my records. I would bet that most other forms of demineralized water would work fine too (distilled, cation/anion exchange that is not based or replacing water hardening minerals with salt).
I just think that the steam cleaning method is a big hassle compared to wet cleaning and vacuuming. I hardly ever find a used record that does not clean up by using such machines, and I never let my own records get terribly dirty. I have the same Nitty Gritty machine for almost twenty years and it does a good job and is easy to use. I don't use the automatic fluid dispensing feature (I apply fluid from a squirt bottle) and I don't even use the rubber wheel to turn the record (I prefer to turn by hand so I can scrub back and forth). Thus, for me, the cheapest machine would be enough. The idea of having to get out a steam cleaner, fill it with water, wait for it to heat up, clean the record, dry the record, empty the steamer, etc. is just too much trouble for regular, every day use.