Freshwater Blend Calculator

Dial in cleaner blends for healthier plants. Enter source readings, choose units, get exact split. Save results to share, print, and reuse later easily.

Calculator Inputs

Enter TDS/EC for Source A.
ppm or electrical conductivity.
Enter TDS/EC for Source B.
Use the same meter type for best results.
Desired blended TDS/EC.
Pick the unit you prefer.
Total blend volume you want to prepare.
Outputs show both liters and gallons.
Matches how your meter converts EC to ppm.
Prepares extra volume for losses and spillage.
Round volumes to match your measuring tools.

Example Data Table

Source A (ppm) Source B (ppm) Target (ppm) Final Volume (L) Result A (L) Result B (L)
1202070201010
2203080307.522.5
150050103.3336.667
Examples assume no safety margin and minimal rounding.

Formula Used

This tool uses a linear mixing balance. When you blend two sources, the final concentration is the weighted average of each source, based on volume.

How to Use

  1. Measure both water sources with the same meter when possible.
  2. Enter Source A and Source B readings, then choose their units.
  3. Enter your desired target reading and the final volume to prepare.
  4. Select the EC-to-ppm scale that matches your meter settings.
  5. Optional: add a safety margin and choose a rounding increment.
  6. Click Calculate to get exact volumes for each source.
  7. Use the download buttons to save results for later use.

Why Blending Matters

Freshwater blending helps you control dissolved solids before nutrients are added. In gardens, high mineral water can push EC up, cause salt stress, and reduce uptake of calcium, magnesium, and micronutrients. Blending two sources lets you lower a harsh supply or raise a very soft supply so irrigation stays stable across beds, pots, and reservoirs.

Choosing Source A and Source B

Use the cleanest source as your “dilution” water and the stronger source as your “mineral” water. Measure both with the same meter, and rinse the probe between samples to avoid carryover. If you only have one source, you can treat rainwater, RO water, or stored water as a second input to reach a predictable mix.

Setting Realistic Targets

A target should match plant sensitivity and your nutrient program. Seedlings and leafy greens often prefer lower starting EC, while mature ornamentals may tolerate higher baseline minerals. Avoid targets outside the range of your two sources because no blend can exceed the higher value or drop below the lower value. If the target is out of range, change the sources or target. When in doubt, aim slightly lower, then add nutrients gradually.

Accounting for Meter Scales and Temperature

EC meters may display conductivity, or convert to ppm using different scales. A 500-scale or 700-scale conversion changes the number, not the water. Choose the same scale your meter uses so records remain comparable. Temperature compensation also matters: let samples reach similar temperature, and keep readings consistent by measuring in the same container depth. Calibrate periodically with fresh standard solution.

Recordkeeping and Consistency

Small variations accumulate over time, so log your inputs and blend outputs. The calculator’s safety margin helps cover hose losses, filter waste, or spillover. Rounding to a practical increment improves repeatability with jugs or flow meters. Over a season, consistent blending reduces surprises, keeps fertigation predictable, and supports healthier root zones and more uniform growth. Review trends monthly to spot drifting source quality after storms or maintenance.

FAQs

Can I blend using ppm instead of EC?

Yes. Enter readings in ppm, or enter EC and let the tool convert using your selected scale. Keep the same unit and scale each time so your logs stay comparable.

What if my target equals Source A or Source B?

If the target matches a source, the blend volume for that source becomes the full batch, and the other source becomes zero. This is normal and confirms no mixing is needed.

Why does the calculator warn about out-of-range targets?

A blend cannot be lower than the lower source or higher than the higher source. The warning helps you avoid impossible mixes and prompts you to adjust sources, treatment, or your target.

How should I choose the EC-to-ppm scale?

Use the scale your meter is set to. Many meters use 500 or 700. The scale changes the displayed ppm number, not conductivity, so matching the meter keeps results and records consistent.

Does blending remove chlorine or chloramine?

No. Blending only adjusts dissolved solids concentration. If disinfectants are a concern, use activated carbon, aging, or other treatment methods, then re-test and blend again if needed.

What does the safety margin do?

It increases the final batch volume by your chosen percentage, then recomputes source volumes. This helps cover losses from line flushing, filter waste, or spills while keeping the target reading intact.

Built for practical irrigation blending and reservoir prep.

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Important Note: All the Calculators listed in this site are for educational purpose only and we do not guarentee the accuracy of results. Please do consult with other sources as well.