Enter your water volume and concentration goals. Results appear above after submission.
These examples assume pure salt and show approximate results.
| Scenario | Volume | Current | Target | Salt to add |
|---|---|---|---|---|
| Start from zero, mild brine | 10 L | 0 g/L | 5 g/L | 50 g |
| Top-up from a reading | 25 L | 2 g/L | 6 g/L | 100 g |
| Small batch for spot work | 1 US gal | 0 g/L | 0.3% (w/v) | 11.36 g |
| Too salty, dilute to target | 5 L | 8 g/L | 4 g/L | Add 5 L water |
- g/L from ppt: 1 ppt ≈ 1 g/L.
- g/L from % (w/v): g/L = % × 10.
- g/L from mg/L or ppm: g/L = value ÷ 1000.
Salt to add (pure grams):
grams_pure = (target_gL − current_gL) × volume_L
Salt to add (product grams, purity-adjusted):
grams_product = grams_pure ÷ (purity% ÷ 100)
Dilution when current exceeds target: keep total salt constant and increase water volume.
final_volume_L = (current_gL × volume_L) ÷ target_gL
add_water_L = final_volume_L − volume_L
- Choose your water volume and unit.
- Enter your target concentration and select a unit.
- Optionally enter a current concentration reading.
- Set salt purity if your product is not pure.
- Click Calculate to show results above the form.
- Use CSV or PDF downloads for logs and labels.
- Adding salt to soil can damage structure and plants.
- Use measured solutions for controlled, limited applications.
- Always label mixed liquids and keep them away from children.
Target salinity and crop tolerance
Salinity targets vary widely by crop, substrate, and growth stage. Most vegetables and ornamentals perform best with low total dissolved salts, while halophytes and some turf species tolerate higher levels. Start with a conservative goal unless you have soil, runoff, or solution analyses. This calculator converts a clear target into a measurable dose, helping you avoid overshooting and irreversible plant stress.
Working with water volume and units
Accurate volume is the foundation of any dosing plan. Measure tank dimensions, read calibrated markings, use flow meters, or estimate reservoir capacity from fill time and pump rate. Select liters, cubic meters, or gallons, then let the tool normalize everything internally. Consistent units prevent hidden errors, especially when switching between ppm, mg/L, and percent concentration displays.
Purity, blending, and staged additions
Commercial salts can contain moisture and anticaking agents, so purity affects the true sodium chloride delivered. Enter purity to correct the effective mass that actually dissolves. For large increases, pre-dissolve salt in a bucket and add in stages, mixing thoroughly between additions. Staged dosing protects roots, avoids localized spikes, and improves repeatability across multiple batches or seasonal adjustments.
Interpreting concentration readings
Meters may report ppm, mg/L, or percent, and some display NaCl‑equivalent while others estimate TDS from conductivity. Choose the same basis for both your current reading and your target. After dosing, circulate the solution long enough to homogenize, then recheck. Use temperature compensation, rinse probes, and verify calibration fluids periodically to keep readings trustworthy.
Recordkeeping and safety practices
Document each adjustment so you can learn from outcomes and communicate clearly with staff. Export CSV for logs and generate a PDF label for the tank, including time, volume, target, and dose. Store salts dry, avoid inhaling dust, and keep concentrates away from children and pets. If you are dosing irrigation water, confirm local recommendations and monitor soil salinity to prevent long-term buildup. Review results after rainfall, leaching events, or crop rotation decisions.
Which concentration unit should I use?
Use the unit that matches your test method. If your meter shows ppm or mg/L, choose that. If you track percent by weight, choose percent. Keep current and target in the same unit basis.
Why does salt purity change the dose?
Purity adjusts for moisture and additives. A 95% product delivers only 0.95 of the labeled mass as sodium chloride. The calculator increases the required weight so the dissolved NaCl reaches your target concentration.
Is salt addition safe for garden soil?
Routine salt addition to soil is usually unsafe. Sodium can disperse soil structure and reduce water infiltration, and many plants are salt sensitive. Use this tool mainly for tanks, reservoirs, or controlled solutions, and follow local guidance.
My meter reports EC. How do I use it here?
Convert EC to a concentration estimate using your meter’s stated factor or a lab correlation for your water. Many meters estimate TDS by multiplying conductivity by a factor. Apply the same factor consistently for current and target values.
Why is the calculator showing zero or negative salt to add?
If your current concentration is at or above the target, additional salt is not needed. A negative value indicates the target is lower than the current reading; you would dilute with fresh water instead.
What should I record after each adjustment?
Log the date, water volume, current reading, target, salt type, purity, and the final dose. Recheck after mixing and note the verified reading. The CSV and PDF outputs help standardize these records.