I have well water at my new house with a water softener. We have to use the green bags of salt with the Rust Remover because of the high iron content. Under the kitchen sink I beleive is a RO unit, it has three canisters the water goes through before it comes out a faucet on the sink. I am guessing this water is okay to use, the guy from the water place came out and tested the water from that faucet with a little meter that tests for particles in the water and it was under 20 and the normal water out of the kitchen faucet was around 400. I have no clue what unit of measure it was but it sounded good. My question is will the well water coming out of the ro unit be as pure as the water I normally get filled up at the grocery store?