Water purity question

[karanoff]

I've been reading, on a paph blog, about testing water for impurities with a TDS meter since the writer of this blog found that watering orchids with water treated with reverse osmosis (RO) produced better and "happier" plants. I have well water (I live in rural Maine) and know I have high iron in the water. I have a special system for filtering it out if I use a de-rusting additive but I think the de-rusting additive adds sodium. Should I test my water (there's no chlorine as far as I know)? If so, can I do it with an inexpensive ($20) TDS meter or should I get a more thorough test using professional resources? And should I get an RO system?

Karen