Calculator
Example Data Table
| Scenario | Inputs | Key Output |
|---|---|---|
| New batch | Stock 2.40, Water 0.30, Target 1.60, Final 10 L | Use 6.154 L stock and add 3.846 L water |
| Dilute existing | Current 2.10, Water 0.30, Target 1.60, Current 8 L | Add 2.400 L water to reach 10.400 L |
| Blend two mixes | A 2.20, B 0.40, Target 1.50, Final 12 L | Use 7.333 L of A and 4.667 L of B |
Formula Used
The calculator assumes EC blends linearly by volume: ECfinal = (EC1·V1 + EC2·V2) / (V1 + V2).
- New batch from stock + water: Vstock = (ECtarget − ECwater) / (ECstock − ECwater) · Vfinal.
- Dilute existing by adding water: solve (ECcurrent·Vcurrent + ECwater·Vadd)/(Vcurrent+Vadd) = ECtarget.
- Blend two solutions: treat them like stock and base, using the same ratio method.
How to Use This Calculator
- Select the calculation mode that matches your task.
- Choose liters or gallons, then enter your EC values.
- Enter the volume you want to end with (or start from).
- Press Submit to see the result above the form.
- Mix, re-check EC, then download CSV or PDF.
EC Planning for Consistent Feeding
The sections below share practical, data-driven guidance for using the calculator reliably.
Target EC Ranges by Growth Stage
EC targets vary with crop type, light intensity, and substrate. As a general reference, seedlings often sit near 0.6–1.2 mS/cm, vegetative growth around 1.2–2.0 mS/cm, and heavy fruiting can reach 2.0–3.0 mS/cm when plants are actively transpiring. Use your meter readings and plant response to fine-tune.
Stock Strength and Dilution Efficiency
Stronger stock solutions reduce measuring steps but raise error impact. For example, increasing stock from 2.4 to 3.0 mS/cm cuts stock volume needed for the same target, yet small measurement mistakes can shift EC more. The calculator displays both percentage and dilution factor to help compare repeatability across mixes.
Water EC as a Hidden Input
Source water EC changes seasonally and by filter condition. A rise from 0.30 to 0.55 mS/cm can reduce nutrient headroom, especially for sensitive crops. Enter water EC each time you mix; this keeps the computed stock volume realistic and prevents unintended overfeeding.
Temperature and Meter Consistency
Many meters apply automatic compensation, but results can still drift between cold and warm solutions. When you enable normalization, the calculator adjusts values toward a 25°C reference using a typical coefficient (~1.9%/°C). Treat it as a consistency aid, not a lab-grade correction.
Example Dataset You Can Record
Use this compact dataset format for logs and audits:
| Date | Mode | Inputs (EC/Vol) | Output (Volumes) |
|---|---|---|---|
| 2026-01-29 | New batch | 2.40 / 0.30 / 1.60 / 10 L | Stock 6.154 L, Water 3.846 L |
| 2026-01-29 | Dilute existing | 2.10 / 0.30 / 1.60 / 8 L | Add Water 2.400 L, Total 10.400 L |
| 2026-01-29 | Blend two | 2.20 / 0.40 / 1.50 / 12 L | A 7.333 L, B 4.667 L |
FAQs
1) Why must target EC be between water and stock?
Linear mixing cannot create a value outside the range of the two inputs. If your target is higher than stock or lower than water, you need a different stock strength or a different base solution.
2) Can I use this for hydroponics and soil feeding?
Yes. EC dilution math is the same. The difference is your crop’s safe EC range and how quickly salts accumulate, which depends on runoff, media buffering, and watering frequency.
3) What unit should I use: mS/cm or µS/cm?
This calculator uses mS/cm. If your meter shows µS/cm, divide by 1000 to convert. For example, 1600 µS/cm equals 1.6 mS/cm.
4) Does “dilution factor” equal “how many times weaker”?
It indicates how much the stock portion is stretched in the final mix. A dilution factor of 2× means the stock volume is doubled by adding an equal amount of base liquid.
5) Why do my readings differ after mixing?
Incomplete mixing, temperature differences, meter calibration, or nutrient precipitation can shift readings. Mix well, wait a minute, and re-check. Calibrate periodically using the correct standard solution.
6) Should I add nutrients to water or water to nutrients?
Add concentrate into water while stirring to reduce localized high-strength zones. This helps prevent precipitation and improves repeatability, especially with multi-part nutrient systems.
7) How should I store CSV/PDF mix sheets?
Save by crop and week, and include water source notes. Consistent records help spot drift in water EC, dosing habits, and plant tolerance over time.