Aquaponic Feed-to-Plant Ratio Calculator
Calculate the balanced ratio of fish feed input to plant growing area in aquaponic systems. Match nutrient output from fish to plant uptake capacity.
Hydroponic Nutrient Solution Calculator
Calculate stock solution dilution ratios, target EC, and pH ranges for hydroponic nutrient management. Mix precise nutrient solutions for soilless growing.
mS/cm
mS/cm
liters
Tap/RO baseline
mS/cm
days
Dilution Ratio⧉
1 : 21.7
22.7x total dilution
Stock Solution Needed⧉
4.40 L
+ 95.6 L water for 100 L total
TDS (500 scale)⧉
1,250 ppm
Common for hydroponics
TDS (700 scale)⧉
1,750 ppm
Hanna, Milwaukee meters
Volume per Plant⧉
8.3 L
12 plants in 100 L
Monthly Water Usage⧉
429 L
Changed every 7 days
Monthly Stock Used⧉
18.9 L
227 L/year
Nutrient Status
EC: 2.5 mS/cm
Ideal for Tomato: 2.5 mS/cm
pH: 7.0
Ideal range: 5.8 - 6.5
Approx. NPK at Target EC
| Nutrient | ppm | Visual |
|---|---|---|
| Nitrogen (N) | 3 ppm | |
| Phosphorus (P) | 1 ppm | |
| Potassium (K) | 4 ppm |
EC Mixing Reference
| Target EC | Stock Needed (L) | TDS-500 | TDS-700 |
|---|---|---|---|
| 0.5 mS/cm | 0.40 | 250 ppm | 350 ppm |
| 0.8 mS/cm | 1.00 | 400 ppm | 560 ppm |
| 1.0 mS/cm | 1.40 | 500 ppm | 700 ppm |
| 1.2 mS/cm | 1.80 | 600 ppm | 840 ppm |
| 1.5 mS/cm | 2.40 | 750 ppm | 1,050 ppm |
| 1.8 mS/cm | 3.00 | 900 ppm | 1,260 ppm |
| 2.0 mS/cm | 3.40 | 1,000 ppm | 1,400 ppm |
| 2.5 mS/cm | 4.40 | 1,250 ppm | 1,750 ppm |
| 3.0 mS/cm | 5.40 | 1,500 ppm | 2,100 ppm |
Crop EC and pH Reference
| Crop | EC (mS/cm) | pH Range | N ppm | K ppm |
|---|---|---|---|---|
| Lettuce / Greens | 1.2 | 5.5 - 6.5 | 150 | 200 |
| Tomato | 2.5 | 5.8 - 6.5 | 200 | 300 |
| Pepper | 2.2 | 5.8 - 6.5 | 180 | 280 |
| Cucumber | 2 | 5.5 - 6 | 190 | 270 |
| Strawberry | 1.8 | 5.5 - 6.5 | 130 | 200 |
| Herbs (Basil, Mint) | 1.4 | 5.5 - 6.5 | 120 | 180 |
| Cannabis | 2 | 5.8 - 6.2 | 200 | 250 |
Planning notes, formulas, and examples
About the Hydroponic Nutrient Solution Calculator
Hydroponic systems deliver nutrients directly to plant roots through water, making precise nutrient management essential. Stock solutions — concentrated fertilizer mixes — are diluted to a working strength measured by Electrical Conductivity (EC) in mS/cm or Total Dissolved Solids (TDS) in ppm.
This page helps determine the dilution ratio to reach your target EC from a stock solution, and converts between EC and TDS. It also shows the recommended EC and pH ranges for common hydroponic crops.
In hydroponics, small dilution mistakes show up fast in the crop. This page is meant to turn reservoir mixing into a repeatable target rather than a rough estimate.
When This Page Helps
Hydroponic nutrient mistakes are expensive because the root zone has almost no buffering. This page helps keep dilution and EC targets aligned with the crop stage.
How to Use the Inputs
- Enter your stock solution concentration (EC in mS/cm).
- Enter your target working solution EC.
- Review the dilution ratio (stock : water).
- Enter an EC value to convert to TDS (ppm).
- Compare your target to crop-specific EC and pH recommendations.
Formula used
Dilution Ratio = Stock EC / Target EC
Parts Water = Dilution Ratio − 1 (for 1 part concentrate)
TDS (ppm) ≈ EC (mS/cm) × 500 (using 500 scale)
or TDS (ppm) ≈ EC (mS/cm) × 700 (using 700 scale)Example Calculation
Result: 1:24 dilution ratio
A stock solution at 50 mS/cm diluted to a target of 2.0 mS/cm: 50 / 2.0 = 25× total volume. That's 1 part stock to 24 parts water. At EC 2.0 mS/cm, TDS ≈ 1,000 ppm (500 scale).
Tips & Best Practices
- Always add nutrients to water, not water to nutrients, to prevent precipitation.
- Use separate A and B stock solutions for calcium-containing formulas to prevent lockout.
- Calibrate EC and pH meters weekly for accurate readings.
- Lettuce: EC 0.8-1.4 mS/cm. Tomatoes: EC 2.0-3.5 mS/cm. Strawberries: EC 1.0-1.5 mS/cm.
- Target pH 5.5-6.5 for most hydroponic crops — adjust with phosphoric acid (down) or potassium hydroxide (up).
- Replace nutrient solution every 1-2 weeks in recirculating systems to prevent imbalances.
Nutrient Solution Management
Daily monitoring of EC and pH is essential in hydroponics. EC rises as plants take up water faster than nutrients (concentrate solution). EC drops as plants take up nutrients faster than water (dilute solution). Top off with plain water or weak solution to maintain target EC.
Common Hydroponic Formulations
The Hoagland solution is a classic research formula. Commercial two-part (A+B) or three-part (Grow/Micro/Bloom) systems are more practical. Each provides a complete nutrient package when mixed at the recommended ratios. Adjust ratios for vegetative vs. flowering growth stages.
Water Quality Baseline
Start with low-EC source water (< 0.3 mS/cm). Reverse osmosis (RO) water gives a clean baseline. If using well or tap water, test for baseline EC, alkalinity, and specific ions (calcium, sodium, chloride) to account for their contribution to the final solution.
Sources & Methodology
Last updated:
Frequently Asked Questions
Electrical Conductivity (EC) measures the total ion concentration in a solution. Higher EC means more dissolved nutrients. It doesn't tell you which nutrients are present, just the overall strength. Measured in mS/cm (millisiemens per centimeter).
EC measures conductivity directly. TDS (Total Dissolved Solids) is estimated from EC using a conversion factor — typically 500 or 700 depending on the meter manufacturer. EC is the more universal standard in professional hydroponics.
Calcium sulfate and calcium phosphate are relatively insoluble. If calcium and sulfate or phosphate ions are concentrated together in one stock, they precipitate out of solution. Separate A (calcium + nitrate) and B (phosphate + sulfate + micronutrients) stocks prevent this.
Most hydroponic crops perform best at pH 5.5-6.5. Below 5.0, micronutrient toxicity can occur. Above 7.0, iron and other micronutrients become unavailable. Check pH daily and adjust as needed.
In recirculating systems, change every 1-2 weeks or when EC drifts significantly from target. In drain-to-waste systems, fresh solution is delivered each irrigation. Monitor EC and pH trends to determine change frequency.
Most garden fertilizers are designed for soil and may not dissolve fully or contain the right nutrient ratios for hydroponic use. Use fertilizers specifically formulated for hydroponics with fully soluble salts and complete micronutrient packages.
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