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HM Digital TDS-3 Handheld TDS Meter


HM Digital TDS-3 Handheld TDS Meters

    ✔️ 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!  
    ✔️ The perfect tool to test to see if your Reverse Osmosis Drinking Water System membrane needs replacement.  
    ✔️ The videos show how to use a TDS meter to test your membrane and measure total dissolved solids.


    ✔️ Ideal for commercial use.
    ✔️ Includes a carrying case with belt clip.
    ✔️ Highly efficient and accurate due to its advanced microprocessor technology.
    ✔️ Hold Function: saves measurements for convenient reading and recording.
    ✔️ Auto-off function: the meter shuts off automatically after 10 minutes of non-use to conserve batteries.
    ✔️ Measurement Range: 0-9990 ppm. From 0-999 ppm, the resolution is in increments of 1ppm. From 1000 to 9990 ppm, the resolution is in increments of 10ppm, indicated by a blinking 'x10' image.
    ✔️ Built-in digital thermometer
    ✔️ Display: large and easy-to-read LCD screen.
    ✔️ Factory Calibrated: our meters are calibrated with a 342 ppm NaCl solution.
    ✔️ Meters can be re-calibrated with a mini-screwdriver.
    ✔️ Also available in x10" mode: reads in increments only of 10 ppm (0-9990 ppm).
    ✔️ Click here for a photo of the meter with its case.✔️Need help deciding which meter is right for you, view our TDS/EC Meter Selection Guide.


    ✔️ TDS Range: 0 - 9990 ppm (mg/L)
    ✔️ Temp. Range: 0 - 80 degrees Celsius
    ✔️ Resolution: 0-999: 1 ppm; 1000-9990: 10 ppm (indicated by a 'x10' icon)
    ✔️ Temperature Resolution: 0.1 degree Celsius (Celsius only)
    ✔️ Accuracy: +/- 2%
    ✔️ EC-to-TDS Conversion Factor: NaCl (avg. 0.5)
    ✔️ ATC: Built-in sensor for Automatic Temperature Compensation of 1 to 50 degrees Celsius (33 to 122 degrees Fahrenheit)
    ✔️ Power source: 2 x 1.5V button cell batteries (included) (LR44 or equivalent)
    ✔️ Battery life: 1000 hours of usage
    ✔️ Dimensions: 15.5 x 3.1 x 2.3cm (6.1 x 1.25 x 1 inches)
    ✔️ Weight with case: 76.5g (2.7 oz)
    ✔️ Weight without case: 56.7g (2 oz)


    Product Number KIT TDS-3

    All products include FREE standard shipping in Canada!

    Customer Reviews

    Based on 6 reviews
    Geoff G. (Whistler, CA)
    A Succinct Little Unit.

    There's 2 buttons, not much to say really, but the meter appears to be accurate and works exactly as expected. I'm getting the most use out of my TDS meter in checking the dissolved solids in my shrimp aquarium but it's nice to have around to monitor the status of my reverse osmosis membrane over time.

    Unit works well and I can easily recommend it to anyone who's interested in measuring total dissolved solids in water.

    Hi Geoff,
    Thanks for your purchase, detailed feedback and the great recommendation!
    We look forward to helping you again soon.
    Take care and stay safe.

    Jamie Y. (Campbellford, CA)
    TDS meter

    Works well and as it is supposed to.

    Hi Jamie,
    Thank you for your business, and for letting us know it works well -- and you're welcome!
    We look forward to helping you again soon.
    Take care and stay safe.

    MIke B. (Toronto, CA)
    Handheld TDS Meter

    Happy with this device. Easy to use and the price was right. Certainly gives me peace of mind about our RO water.

    Hi Mike, Thank you for your business,and for letting us know!
    We look forward to helping you again soon.
    Take care and stay safe.

    Edgard C. (Calgary, CA)
    You have to double check !!!

    A TDS meter is a valuable tool to double check that your Reverse Osmosis System is doing its job.The test lamp on my ROS system has said ok for the last 4 years. So how do you know if you are the filter or if the filters are still filtering (great punch line Gary, I use it whenever I talk with a fellow water well drinker) ? The results from our ROS is 28-31. Our unfiltered well water is 385.This TDS meter does the job and saves you from buying new filters for nothing. You're saving money and being green at the same time. It’s a no brainer.

    Katy (Bayfield, CA)
    HM Digital TDS-3 Handheld TDS Meter

    Excellent tool for helping monitor our well water and our water treatment systems

    Shipping Policy

    We offer FREE Shipping anywhere in Canada. Once your order is placed, we process it the next business day and ship via ground transportation. In very remote locations, whenever the shipping costs become prohibitive we reserve the right to either cancel the order or ask that you contribute to the shipping costs, it's up to you. Your items may take anywhere from a few days up to a few weeks to arrive.

    If you have any special shipping requirements, like requiring a signature at time of delivery, please leave a message in the "Special instructions for seller" section while checking out. If you order multiple products they may not all arrive at the same time as we ship from multiple warehouses and each item will be shipped directly to you. If no one is home when your order is delivered it will be left for you but we cannot assume responsibility for your order once it has been dropped off.

    If you have any questions please contact us at

    Thank you for your order, we appreciate your business!


    Excluded Items

    We do not offer refunds or returns on items built to order including Aclarus Ozone systems, Reverse Osmosis systems larger than 500 gpd or water softeners/iron filters over 1 cubic foot. 


    Our policy lasts 30 days. If 30 days have gone by since your purchase, unfortunately, we can’t offer you a refund or exchange.

    To be eligible for a return, your item must be unused and in the same condition that you received it. It must also be in the original packaging.

    To complete your return, we require a receipt or proof of purchase.

    Please do not send your purchase back to the manufacturer.


    Once your return is received and inspected, we will send you an email to notify you that we have received your returned item. We will also notify you of the approval or rejection of your refund.

    If you are approved, then your refund will be processed, and a credit will automatically be applied to your credit card or original method of payment, within a certain amount of days.

    Late or missing refunds

    • If you haven’t received a refund yet, first check your bank account again.
    • Then contact your credit card company, it may take some time before your refund is officially posted.
    • Next contact your bank. There is often some processing time before a refund is posted.
    • If you’ve done all of this and you still have not received your refund yet, please contact us at

    Sale items

    Only regular priced items may be refunded, unfortunately, sale items cannot be refunded.


    We only replace items if they are defective or damaged. If you need to exchange it for the same item, send us an email at and send your item to: The Water Store 1004 King Street Midland Ontario CA L4R0B8.


    To return your product, you should mail your product to:

    The Water Store
    1004 King Street
    Midland Ontario CA L4R0B8

    You will be responsible for paying for your own shipping costs for returning your item. Shipping costs are non-refundable. If you receive a refund, the cost of return shipping will be deducted from your refund.

    Depending on where you live, the time it may take for your exchanged product to reach you, may vary.

    If you are shipping an item over $75, you should consider using a trackable shipping service or purchasing shipping insurance. We don’t guarantee that we will receive your returned item.

    Still Got Questions?

    Not to worry, we're here to help. Let us know what questions you have about HM Digital TDS-3 Handheld TDS Meter and one of our experts will get back to you shortly.