Library · Water, nutrients & feed
Source Water Decoder.
Source Water Decoder
Decode your municipal water report or well test. See what your starting water means for nutrient delivery, alkalinity, hardness, and pH stability.
Why source water matters
Two growers using the same recipe at the same dilution get different solutions if their source waters differ. A 145 ppm N target arriving in soft RO water is not the same as 145 ppm N arriving in 80 mg/L alkalinity well water.
Source water carries:
- Starting EC — eats into your recipe headroom. RO output 0.05 mS/cm leaves room for full nutrient delivery; well water at 0.5 mS/cm means your recipe target EC of 1.5 must rise to 2.0 to deliver the same nutrient concentration.
- Starting pH — most well and municipal water sits at 7.0-8.5; almost no recipe targets that range. You'll be acidifying.
- Alkalinity (HCO₃⁻ / CO₃²⁻) — the buffer that *resists* your acidification. High alkalinity (>120 mg/L CaCO₃) requires significant acid injection just to bring water to recipe pH; low alkalinity drifts more.
- Hardness (Ca + Mg) — counts toward your recipe target. High hardness means you don't need to add as much Ca or Mg; soft water means you must.
- Sodium and chloride — competitors / antagonists. High Na is a soil-structure risk and competes with Ca/K uptake. High Cl can be toxic at scale.
- Trace elements — some well water already has Fe, Mn, micronutrients you don't need to add.
What this decoder does
Enter your water test results above. The decoder will tell you:
- Whether your water is suitable as-is, needs treatment, or should be RO-treated
- How much your alkalinity will resist pH adjustment
- What Ca and Mg the water already provides toward your recipe
- Whether sodium or chloride levels are concerning
- The Sodium Adsorption Ratio (SAR) — a soil-structure risk indicator
Reference ranges
| Property | Excellent | Acceptable | Treatment recommended |
|---|---|---|---|
| EC (mS/cm) | < 0.3 | 0.3 – 0.7 | > 0.7 |
| pH | 6.5 – 7.5 | 6.0 – 8.0 | outside |
| Alkalinity (mg/L) | < 80 | 80 – 150 | > 150 |
| Hardness (mg/L) | 50 – 150 | 150 – 250 | > 250 |
| Sodium (Na, ppm) | < 30 | 30 – 70 | > 70 |
| Chloride (Cl, ppm) | < 70 | 70 – 140 | > 140 |
| SAR | < 3 | 3 – 6 | > 6 |
Common treatments
- Acid injection (phosphoric, nitric, citric, or sulfuric acid) — to bring source pH down and consume alkalinity before nutrient mixing. Phosphoric acid adds P; nitric adds N; citric is organic-compliant but expensive.
- Reverse osmosis (RO) — strips ~95% of dissolved solids. RO output requires re-mineralization for healthy plant nutrition. Best for very hard / high-Na / high-alkalinity sources.
- Blending — mix RO with rain or well water to achieve target starting profile.
- Dechlorination — for municipal water with chlorine or chloramines. Activated carbon, vitamin C, or aging-in-tank.
- Iron removal — for well water with Fe staining. Aeration + filtration or ion exchange.
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