If you clean glass with a water-fed pole, the TDS meter is the tool that tells you whether the next hour of work is going to dry spot-free or dry streaked. The HM Digital Handheld TDS Meter is the pocket instrument window cleaners use to check total dissolved solids in their purified water before the pole goes up, and to know when a DI resin bed or RO membrane has stopped doing its job. It is a small purchase that prevents the expensive mistake, which is discovering the problem after the building is done.
Built for: common use cases
- Window cleaning contractors running water-fed pole systems who need to verify purity before starting a job.
- Operators monitoring DI resin exhaustion so they change media on data rather than on a guess.
- Pressure washing and soft-wash crews checking source water and final rinse quality.
- Anyone commissioning or troubleshooting an RO or RO/DI cart and needing an inlet and outlet reading.
- Solar panel and fleet washing operations where spot-free rinse is the whole deliverable.
Reading the number
TDS is measured in parts per million and represents the dissolved minerals and impurities left in the water. Those minerals are what stays behind on the glass when the water evaporates, which is why tap water spots and purified water does not. For spot-free window cleaning, a reading of 10 ppm or lower at the pole is the generally accepted working target. Watching that number climb over a few jobs is the earliest and clearest sign that resin needs changing, well before the results on the glass start telling you the same thing at a much higher cost.
The meter reads temperature as well as TDS, which is useful because dissolved solids readings are temperature dependent. The hold function freezes a reading so you can take a measurement at the cart and record it without contorting yourself to see the display, and auto-off keeps the battery from draining in a van drawer.
Handling note
This meter is not fully waterproof. Submerge the testing tip only. Dunking the body is the most common way these instruments are killed, and it is entirely avoidable.
Specifications
- Measures total dissolved solids and temperature
- Large LCD display with hold function
- Auto-off function to preserve battery life
- Factory calibrated
- Durable translucent blue housing
- Length: 8.25 inches
- Width: 2.75 inches
- Height: 0.75 inches
- Weight: 0.13 lbs
- Testing tip only is water safe; the meter body is not waterproof
Frequently asked questions
What TDS reading do I need for spot-free window cleaning?
A reading of 10 ppm or lower at the pole is the generally accepted working target for spot-free results. Many operators aim lower on dark glass and high-visibility work.
Can I submerge the meter?
No. Only the testing tip should go into the water. The body of the meter is not waterproof and submerging it will damage the instrument.
Does it need calibrating out of the box?
It ships factory calibrated. Operators who rely on the reading commercially typically verify it periodically against a known calibration solution.
How does this tell me when to change DI resin?
Take a reading at the pole at the start of each job and log it. A steadily rising number means the resin bed is approaching exhaustion, giving you time to change media before results suffer.
Does it measure water temperature too?
Yes. It reads both TDS and temperature, which matters because dissolved solids measurements vary with temperature.
Is it useful outside window cleaning?
Yes. It is commonly used for pressure washing rinse water, solar panel and fleet washing, and general RO or RO/DI system monitoring.
Discount Cleaning Products is an authorized dealer supplying commercial cleaning contractors, facility maintenance teams and building service crews across the United States. Our US-based staff works with this equipment every day and can help you confirm fit, sort out compatibility questions and source the rest of what your crews run through.
