The HM Digital TDS-3 handheld water quality tester enables you to determine just how good or bad your water really is! These testers accurately measure the TDS level in your water. Ideal for testing reverse osmosis membrane performance and determining the need for replacement. Ideal for all water purification applications, wastewater regulation, aquaculture, hydroponics, and colloidal silver. Perfect for both consumer or commercial use. Carry one in your pocket or toolbox at all times!
Feature:

• Highly efficient and accurate due to its advanced microprocessor technology.
• Hold function -- Saves measurements for convenient reading and recording, with the sound of a buzzer.
• Auto-off function -- Turns off meter after 10 minutes of non-use to conserve batteries.
• Automatic function -- After operating three minutes in the same condition,the measurement simply stops.
• High TDS Reading -- In case of measuring over 999ppm, the figure of X 10 twinkles automatically.
• Digital Thermometer -- Built-in thermometer with temp button.
• Display -- Large and easy-to-read LCD screen.
• Factory Calibrated -- Recalibration is not necessary, but can be done easily with a watch screwdriver.

The NSF minimum Standard for Percent Rejection is 75%. We recommend replacing the RO membrane once it tests at 80% rejection or lower.

Easy to Follow Instructions!
Using a clean cup or glass, take a sample of your raw feed water. Remove the protective cap from the Tester. Push the "ON" button to activate LCD display. Submerse the tester's probes into the water sample and observe for approx. 10 seconds. Record the results. Repeat the same procedure with a sample of your reverse osmosis (RO) water. If the system is new or the membrane has been replaced, do not test the first tank of RO water. The first tank of product water will contain sanitizer and possibly carbon fines from your new filters. This will cause false reading. Use the following formula to calculate the percentage of solids (TDS) that your membrane is removing: