Can I just dip the probe in water or does it have to be use with tubing?

You can use this in either way.

what's the accuracy of the measurement?

Hi Rick A. I expect to receive the item this upcoming Sunday, once I install it,I will give you feedback, I have purchased several items from HM, such as a inline tds and am finding good results as far as accuracy with in 10 tds from the hand held meter.

can this be used on a 1" copper water main and if so, if I was to insert a 1" copper T, how close does the sensor need to be to the water flow?

Hi, if you are talking about the HM gallons meter, it could be installed with a 1" tee if you can also add a 1/4 fitting either push in type, or a threaded reduced fitting to recieve a push in pvc 1/4 npt. You can also forget the tee and use a pierce fitting on the line that is commonly used to get water to a evaporated cooler. The line should go to the in only feeding the Ro system so your not measuring all of the water being used for everything else. I hope this helps and makes sense.

What is the size of the display?

It's small... approx. 10mm x 20mm, but it's very easy to read.

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HM Digital SM-1 1-Stage Inline TDS Monitor For Single Water Line

Product ID: 30178917

Details

Brand
HM Digital
Included Components
Battery
Installation Type
Under Sink
Manufacturer
HM Digital
Material
Plastic
Model Name
SM-1

💧0-9990 ppm TDS range

🔋Auto-off battery saver

⚙️Advanced microprocessor tech

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Description

💧 Stay ahead of impurities—because your water deserves VIP treatment!

FILTER CHANGE ALERT - Monitor your water’s purity in real-time to know exactly when it’s time to replace filters—never guess again.
PRECISION AT A GLANCE - Accurately measures TDS levels from 0 to 9990 ppm with fine resolution for ultimate water quality insight.
SMART POWER MANAGEMENT - Auto-off feature conserves battery life by shutting down after 10 minutes of inactivity—efficiency meets convenience.
EFFORTLESS INSTALLATION - Quick-connect 1/4 inch John Guest T-fitting ensures seamless integration with any water filtration system.
UNIVERSAL COMPATIBILITY - Perfectly pairs with reverse osmosis systems, coolers, and more, making it the must-have accessory for clean water enthusiasts.

The HM Digital SM-1 is a battery-powered, inline TDS monitor designed for single water lines. Featuring advanced microprocessor technology, it delivers precise TDS readings from 0 to 9990 ppm with an auto-off function to extend battery life. Factory calibrated and easy to install with a John Guest quick-connect fitting, it’s ideal for reverse osmosis and other filtration systems, helping professionals maintain optimal water quality effortlessly.

Specifications

ASIN	B00H1267XY
Best Sellers Rank	#129,939 in Industrial & Scientific ( See Top 100 in Industrial & Scientific ) #77 in Water Purification System Accessories #689 in Substance Analysis Instrumentation
Brand Name	HM Digital
Container Type	Cartridge
Customer Reviews	4.1 4.1 out of 5 stars (32)
Included Components	Battery
Installation Type	Under Sink
Manufacturer	HM Digital
Material Type	Plastic
Model Name	SM-1
Model Number	SM-1
Number of Items	1
Other Special Features of the Product	Multi Stage Filtration, Reduce TDS, Auto-Off function, Advanced Microprocessor Technology
Part Number	343433
Power Source	Battery Powered
Purification Method	Reverse Osmosis
Unit Count	1 Count

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S$51

Duties & taxes included

In stock

Sold byAmazon SINGAPOREDelivered byDesertcartCustomer service byDesertcartReturns14 days · 30 with PRO

Buyer Protection · Full refund if your order doesn't arrive as described.

Desertcart purchases this item on your behalf and handles shipping, customs, and support to SINGAPORE.

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TrustScore 4.5 | 7,300+ reviews

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