Matching a 1500 ppm TDS Solution to Your Meter
Hanna lists this at 1500 mg/L, and the part number tells you which scale that number belongs to. The 442 in HI70442L is the 4-4-2 conversion factor, about 0.65 ppm per µS/cm, which works out near 2,300 µS/cm. It is prepared against NIST traceable potassium chloride, sealed under a tamper-proof cap in a 500 mL bottle. The real conductivity figure across a range of temperatures is printed on the label.
Why the Wrong TDS Calibration Solution Reads Wrong
Meters do not all speak the same dialect. A meter on the ppm500 scale multiplies conductivity by 0.5, and one on ppm700 multiplies by 0.7. Neither will land on the figure printed on this bottle. Check the scale setting before you blame the solution. If your meter is locked to the sodium chloride scale, Hanna makes a 1382 mg/L standard for exactly that case. Past the scale question, the usual rules apply. Let the bottle reach room temperature before anything else, because a cold standard reads low. Give the probe two to three minutes to settle in the solution. Then read the chart on the label for the temperature you are actually working at, rather than assuming the headline figure.
Key Features
- 1500 mg/L on the 4-4-2 scale: About 0.65 ppm per uS/cm, so the meter has to be on the matching scale.
- NIST traceable: Prepared against NIST 2202 potassium chloride, so the value is anchored.
- 500 mL bottle: Enough for routine checks through a full season of feeds.
- Temperature chart on the label: The real conductivity figure at the temperature you are standing in.
- Sealed, tamper proof: Five years from manufacture while the seal stays intact.
- Check your meter scale first: ppm500 and ppm700 meters will not read the label figure on this bottle.
- Alternative scale exists: Hanna HI7032L at 1382 mg/L covers meters on the sodium chloride scale.
Technical Specifications
| Specification | Value |
|---|---|
| Brand | Hanna Instruments |
| Part Number | HI70442L |
| Type | TDS standard solution |
| TDS Value | 1500 mg/L, 1500 ppm |
| Scale | 4-4-2, about 0.65 ppm per uS/cm |
| Approximate Conductivity | Near 2,300 uS/cm, derived from the 0.65 factor |
| Volume | 500 mL, about 16.9 fl oz |
| Composition | Potassium chloride in deionised water |
| Traceability | Prepared against NIST 2202 SRM potassium chloride |
| Label | Temperature chart printed on the bottle |
| Packaging | Air-tight bottle, tamper-proof seal, lot and expiry marked |
| Shelf Life | 5 years from manufacture, unopened |
| Other Sizes | HI70442M 230 mL, HI70442/1L 1 L, HI70442P 25 x 20 mL packets |
| Other Scale | HI7032L at 1382 mg/L, for sodium chloride scale meters |
| Use | Calibrating and checking TDS and PPM meters |