EC to PPM (700 Scale) Converter
Bluelab Truncheons and many EU/AU charts use the 700 scale: EC × 0.7. Same EC, bigger PPM number than the 500 scale — know which one you are on.
Calculator
EC to PPM (700 Scale) Converter
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Bluelab Truncheons and many EU/AU charts use the 700 scale: EC × 0.7. Same EC, bigger PPM number than the 500 scale — know which one you are on.
How to use this calculator
- Enter EC.
- Multiply by 0.7.
- Read PPM.
The formula
700-scale PPM = EC × 700/1000.
What the units mean
µS/cm — microsiemens per centimeter, the unit of electrical conductivity (EC) that meters actually measure before converting to a PPM estimate.
PPM (parts per million) — one part of solute per million parts of the total mixture. The workhorse unit for trace concentrations in water, air, and food.
Worked example
EC 1,400 → 980 PPM (700 scale) vs 700 PPM (500 scale) — same solution!
Quick reference
| EC | PPM (700) |
|---|---|
| 1,000 | 700 |
| 1,400 | 980 |
| 2,000 | 1,400 |
700 scale only.
Where you will actually use this
Truncheon users following US charts (500 scale) underfeed by 40% without realizing.
- Truncheon users
- EU/AU feeding charts
Mistakes that give wrong answers
- Following a 500-scale chart with a 700-scale meter
Key takeaways
- Formula: PPM = EC (µS/cm) × 0.7
- Remember: 700 scale only.
- Watch out for: Following a 500-scale chart with a 700-scale meter
- Next step: run your own numbers in the calculator above, then verify with a measurement — calculated values are only as good as the inputs.
Frequently asked questions
Which scale does Bluelab use?
700 (0.7).