Calculator Inputs
Example Data Table
| Scenario | Volume (L) | Fe Current | Fe Target | Fe Product | Dose (g) |
|---|---|---|---|---|---|
| Leafy greens boost | 500 | 0.20 ppm | 2.00 ppm | 6% Fe (dry) | 15.00 |
| Fruit set support | 800 | 30 ppm K | 60 ppm K | 40% K (dry) | 60.00 |
Formula Used
1) Convert volume to liters
- Liters stay liters.
- US gallons → liters: L = gal × 3.785411784
- Imperial gallons → liters: L = gal × 4.54609
2) Nutrient mass needed
ppm is treated as mg/L, so needed nutrient mass: Needed(mg) = (Target − Current) × Volume(L). If Target ≤ Current, the calculator returns 0.
3) Convert needed nutrient into product dose
- Dry product (% element): Dose(g) = Needed(mg) ÷ (Percent × 10) because 1 g = 1000 mg.
- Liquid product (mg/mL): Dose(mL) = Needed(mg) ÷ Strength(mg/mL).
How to Use This Calculator
- Measure system water volume, including sump and beds.
- Test current nutrient readings with a reliable kit.
- Set realistic targets for your crops and fish.
- Select product type and enter label strength.
- Add the suggested dose in splits, circulate, then retest.
- Export CSV or PDF to track changes and costs.
Aquaponic Nutrient Management Guide
1) Why ppm targets keep systems stable
Aquaponics relies on a narrow balance: fish feed drives nitrogen, while plants and bacteria remove it. Using ppm (mg/L) keeps every adjustment proportional to water volume. For example, raising iron by 1.0 ppm in 500 L requires 500 mg elemental iron. This calculator converts that requirement into a label-based product dose so you avoid guesswork and reduce the risk of sudden swings.
2) Practical target bands growers commonly watch
Targets vary by crops, stocking density, and pH. Many growers start within these working bands and fine‑tune: Fe 1–3 ppm, Ca 40–80 ppm, Mg 10–30 ppm, K 40–100 ppm, and P 5–15 ppm (system‑dependent). Instead of chasing perfect numbers, aim for trends: stable availability, consistent growth, and no fish stress. If you track nitrate instead of N, keep units consistent because NO3 values read higher than elemental N equivalents.
3) Turning product labels into usable dosing data
Dry products usually show a percentage of an element, while liquids often show concentration. The calculator uses two conversions: Dose(g)=Needed(mg)/(Percent×10) for dry products, and Dose(mL)=Needed(mg)/Strength(mg/mL) for liquids. If your label is mg/L, convert to mg/mL by dividing by 1000 before entering it.
4) Safer dosing: split, circulate, retest
Even when the math is correct, biology responds slowly. Split additions into 2–6 steps, circulate for 30–60 minutes, then retest before the next split. If pH shifts, aeration drops, or fish show stress, pause dosing and stabilize. Small, repeatable corrections usually outperform one large correction.
5) Recordkeeping and cost control
Nutrient programs improve when you track results. Use the CSV/PDF exports to log current readings, targets, strengths, and total cost per adjustment. Over time, you can compare seasons, crop changes, and product choices. Consistent records help identify which supplements deliver the best growth response for the lowest cost, and they make it easier to budget recurring items like iron chelate or potassium sources across the full season.
FAQs
1) Does ppm always equal mg/L in aquaponics?
For dilute water solutions, ppm is commonly treated as mg/L. This calculator uses that practical convention for dosing. If your meter reports different units, convert them to mg/L before entering values.
2) Why does the calculator show 0 dose sometimes?
If your target is at or below the current reading, the required increase is zero. The tool avoids negative dosing and assumes you will not remove nutrients using supplements.
3) What if my dry product lists compounds, not elements?
Enter the elemental percentage when possible. If the label lists a compound, use the manufacturer’s “elemental equivalent” value or convert using stoichiometry. When uncertain, choose a conservative target and dose in smaller splits.
4) How do I enter chelated iron products?
Use the iron percentage (dry) or mg/mL (liquid) shown on the label for the iron content. Chelate type affects availability, but the dose calculation still starts with elemental iron required.
5) Can I dose multiple nutrients at once?
You can, but introduce changes gradually. Some supplements also influence pH or hardness. Split doses, watch fish behavior, and retest so you can identify which change caused an improvement or problem.
6) How accurate are the cost estimates?
Costs are estimates based on the prices you enter and the calculated dose. Shipping, wastage, and measurement error are not included. Use exports to compare products consistently across the same volume and targets.
7) What’s a good routine for using this tool weekly?
Test, enter readings, set modest targets, and apply split doses. Record outcomes using CSV/PDF. Repeat after 24–48 hours if needed. This rhythm supports stability while gradually improving nutrient availability.