I seem to be misunderstanding the relationship between hardness and TDS, I think. I was thinking my TDS ppm number should be at least as high as my hardness in ppm. I was told by me dealer that I had 29grs. hardness & 2.5 ppm iron in the water at my house. This is about the same as they tested it at 20 years ago. The electronic TDS meter I use to check my ro system, indicates I have 280 ppm in my hard or soft water, and 7 in my ro water. At 29grs, I thought my TDS should be around 500.

I believe my TDS meter really reads total suspended solids, not just those smaller than two microns. I did check my meter against a water analysis I had run for my cottage water at a lab. It was about 15ppm low. However, the lab results for my cottage showed my hardness, alkalinity, and TDS very close to each other, with the TDS being the highest.

Am I not comparing apples to apples? , thanks.