- Sku: 200219
- Vendor: HM Digital
HM Digital TRM-1 Triple Inline TDS Meter
The HM Digital TRM-1 Triple Inline TDS Meter is the gauge cluster for your RO/DI system. Three inline probes read total dissolved solids at three points at once, typically your source water, after the RO membrane, and after the DI stage, so you can see exactly how each stage is performing and know the moment a membrane or DI resin is spent. Running RO/DI without a TDS meter is guesswork; this one takes the guessing out. It fits any system, including our IceCap 4-Stage RO/DI units, and pairs with an RO float valve for a hands-off water station.
Why Three Readings Matter
- Source water. Shows what your tap is starting at and how hard the membrane has to work.
- After the membrane. A rising number here means the RO membrane is wearing out.
- After DI. Anything above 0 ppm means the DI resin is exhausted and needs changing.
Features
- Three inline sensors with a single digital display, no more pulling samples with a handheld.
- Dual range, 0 to 9990 ppm. 1 ppm resolution to 999 ppm; 10 ppm resolution above that with an x10 indicator.
- Factory calibrated with a 342 ppm NaCl solution and accurate to within 2 percent.
- Auto-off after 10 minutes of non-use to save the batteries.
- Everything included. Three 1/4 inch quick-connect tees with double o-rings and two LR44 batteries in the box.
Installation
Cut the 1/4 inch line at each point you want to monitor and press the tubing into the included quick-connect tees. Mount the display where you can see it, connect the three sensor leads, and you are done. No calibration needed out of the box.
Specifications
| Brand / model | HM Digital TRM-1 |
| Range | 0 to 9990 ppm (dual range) |
| Resolution | 1 ppm to 999 ppm; 10 ppm from 1000 to 9990 ppm |
| Accuracy | Plus or minus 2 percent |
| Conversion factor | NaCl (avg. 0.5) |
| Sensors | 3 inline, 24.5 in cable including sensor |
| Fittings | Three 1/4 in quick-connect tees, double o-ring |
| Power | 2 x 1.5V LR44 button cells (included); auto-off 10 min |
| Display size | 3 x 0.8 x 1.9 in (7.6 x 2 x 4.7 cm), 2.8 oz |
| Water type | Freshwater and saltwater RO/DI |
Recommended Pairings
- IceCap 4-Stage RO/DI 75 GPD, 100 GPD, or 150 GPD systems
- Adjustable RO Float Valve to stop the fill automatically
- AutoAqua Titanium S2 Inline TDS Meter if you only need a single reading
Frequently Asked Questions
Where do I install the three sensors? The usual setup is source water in, after the RO membrane, and after the DI resin. That shows you the whole system at a glance.
What TDS should I see after DI? 0 ppm. Once it starts creeping up, swap the DI resin.
Does it need calibrating? No. It ships factory calibrated and holds its calibration in normal use.
Will it fit my tubing? It uses standard 1/4 inch quick-connect tees, which match nearly every home RO/DI system.
Have a question?
HM Digital TRM-1 Triple Inline TDS Meter
