Kindly advise on the drinking water at my home.

Dear all,
I have elderly people and young children with me. I hail from a mountainous region and the source of water is fresh. We had been using a basic UV sterilising filter from Aquaguard for the past many years with no problem. I recently purchased an LG RO water purifier which also has a UV sterilizer plus a mineral booster which uses 'coral sand' apparently. I bought a tds and pH calculator and was surprised at the results.

Tap water, tds - 10, pH - 9

RO water, tds - 14, pH - 9.9

The tds is increasing and so is the pH. Am i doing more harm than good by using this machine? Is such highly Alkaline Water beneficial to our health?
I know there can be nothing much done about the low tds and the source water itself is very alkaline. But should I go back to using the same old UV sterilizer and return the new RO?

Thank you for the help. Tweet