TDS meters are widely used with reverse osmosis deionization system to monitor the quality of water that your system is producing. For RO systems we recommend inline TDS meters since they are very easy to install and are more accurate than a typical handheld TDS meter.
When it comes to installing the probes that are included with the meters, there are a few different locations to they can be placed, but with most RODI system we highly suggest one probe inserted in the product water line coming out of your membrane and then another after your deionization resin stages. Using a tubing cutter or a sharp razor blade, make a straight cut through the tubing where you want to install the TDS meters probe. Then using the push connect tee that is included with most meters, reconnect the tubing and insert the probe, making sure that the probe’s contacts are perpendicular to the flow of the water through the fitting and not parallel.
We have tried a few different types of TDS meters on the market, but we have grown to like the HM Digital brand since they are made very well, include push connect fittings, and come with a super long lasting battery. HM Digital makes a few different styles of inline TDS meters from a single probe to meters that have 3 probes, allowing you to monitor three separate locations throughout your system by just sliding the selector switch.