Fred,

Take a look at the "Primer on Plant Nutrition" by Bill Argo, PhD, the guy who came up with the MSU fertilizers, that I have on my free info page, particularly the segment on water quality.

For one, Bill mentions that gpg is an outdated measurement equal to 17.1 ppm. That means your water supply is starting at around 300 ppm, and as hardness is usually expressed in terms of CaCO3, it means your water has fairly high alkalinity.

It's interesting that "alkalinity" - the measure of the amount of acid it take to lower the pH to a certain level - is stronger than pH itself. For example, he states that an alkalinity level of 50 ppm is equivalent to a pH of 11!

The only problem with human consumption of RO water is that RO water has a lower pH than we truly need. Our bodies are slightly alkaline, around 7.4 I think, so we need to consume higher pH liquids. Ionized water (higher alkaline level, higher O2 levels) is best for us to consume for numerous reasons.

High acidic levels in the body is the number one cause of chronic inflammation... and chronic inflammation is the number one cause of every disease known to man.

I would refrain from drinking RO water unless absolutely necessary. It's not quite as bad (acidic) as a soda, which is around 3.0 or less. It takes something like 700 cups of pH 7 alkaline water to negate the effects of 1 cup of pH 3 soda! Stay away from acidic things at all costs....

how about water from a refrigerator filter
 

I have been doing orchids since Oct 2007 and it is a real challenge in an apartment/condo. Fortunately I have great true east exposure.
Our municipal water is probably on the soft side. I do use some that I have allowed to sit overnight to"breathe" off the chlorine but I suspect th city uses the non-volatile forms as the water does not smell of it. My refrigerator has a central water filter for the ice and a fresh water tap. These are fairly expensive and seem to be only activated charcoal (perhaps a cell of calcium salts) but no NaCl (table salt-salt)
I used to use purchased distilled water but my experience with these two forms of city water seems to be working. I just wonder if anyone has looked at theses refrigerator water filters and what they are or what they do.
Nick Cirillo