TDS Meter Water Quality Tester Pen TDS-3 With Thermometer

Regular price $49.99 Sale price$18.99
Fast & Free Worldwide Shipping
  • Free Shipping
  • In stock, ready to ship
  • Inventory on the way


This advanced water meter combines TDS (Total Dissolved Solids), EC (Electrical Conductivity), and a temperature meter all in one ergonomically designed pen providing a detailed report on everything you need to know about the quality of the drinking water of your house or for the water used for your pets, fish, and gardening. You can SAVE the measurements for future reference.

What is TDS?

Total Dissolved Solids (TDS) are the total amount of mobile charged ions, including minerals, salts, or metals dissolved in a given volume of water.  TDS which is based on the conductivity is expressed in parts per million (ppm).  TDS includes any conductive inorganic elements present other than the pure water molecules (H20) and suspended solids.

TDS affects everything that consumes, lives in, or uses water, from fish and plants to plumbing and laboratories. Water with a high TDS is known as hard water. Acid rain created hard water.

The hard acidic water then is your greatest enemy. It will destroy every fond hope you have by striking you down when you should be enjoying the fruits of your labors. Crippled joints, repeated surgeries, enlarged hearts, hardened arteries, gall stones, kidney stones, hearing problems, forgetful minds, all draw your activities from the great out-of-doors into creaking rocking chairs, and finally into bed-ridden old folks' homes.

The average person drinks about a gallon of water per day. Adding up the cups of coffee, tea, soft drinks, food, and water, this gallon isn’t too much. At a gallon a day, the average person drinks up to 450, 12-ounce glasses of solids during their life. Think of it… 450 glasses of mineral solids in your system during a lifetime.

For people, appropriate minerals (TDS level) in the water you drink, the more efficiently your body’s cells are hydrated. The higher the TDS level in the water, the greater the probability of harmful contaminants that can pose health risks and/or hinder the absorption of water in the body.


  • 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 for three minutes in the same condition, the measurement simply stops.
  • High TDS Reading -- In the 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 the 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 a false reading. Use the following formula to calculate the percentage of solids (TDS) that your membrane is removing:

Product Weight & Dimensions


6.1 x 1.25 x 1"

Product Weight


Product Details


±2 %

Max Temp (°F)


Measurement Range

0-9990 ppm

Min Temp (°F)


Power Source

2 x 1.5V Button Cell Batteries

1. Do not drop the entire TDS meter in water or dip beyond the maximum immersion level. This unit is not water-tight.
2. Do not store the TDS meter under high temperature or direct sunlight. This will shorten the life.
3. Please avoid impact, heavy pressure, or drop.

We offer a 30 day risk free policy. If for any reason you are not satisfied 30 days after receiving your product, we will repair it for you. All you have to do is contact our knowledgeable customer service team.