TDS-4
Take the guesswork out of knowing when to change your Reverse Osmosis (R.O.) membrane with the TDS-4. This pocket "pen-style" device measures the Total Dissolved Solids (TDS) in water. Ideal as an accessory to a reverse osmosis system, this device allows the user to monitor the performance of an R.O. system and to determine when it is time to change the R.O. membrane.