Nutrient chemistry
Calculate what a fertilizer dose adds, determine a dry-salt dose, or build and analyze a custom stock solution.
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Nutrient contribution
The selected compound can supply more than one nutrient. All listed contributions are included.
Copy a concise dosing summary or reset the calculator for another compound.
Planted-aquarium nutrient guide
A fertilizer salt is defined by its complete chemical formula. KNO3 supplies nitrate and potassium, KH2PO4 supplies phosphate and potassium, and MgSO4·7H2O supplies magnesium and sulfate. The calculator includes every listed contribution.
Dry dosing adds a measured compound mass directly. A stock solution dissolves a known mass into a known liquid volume so a smaller liquid dose can be measured. The underlying nutrient-mass calculation is the same.
Hydration water changes how much nutrient is present per gram. MgSO4 and MgSO4·7H2O therefore produce different results. Always select the exact hydrate state shown on the package.
Nominal tank size can overstate the water being dosed because substrate, hardscape, equipment and air space displace water. Use actual water volume when it is known.
Choose Target → Dose, select nitrate and potassium nitrate, then enter the aquarium volume and desired nitrate increase. The required amount depends on both values and the compound purity.
One gram of pure potassium nitrate in 100 liters adds about 6.13 mg/L nitrate. The exact result is derived from the selected compound formula and purity.
Yes. Potassium nitrate supplies both nitrate and potassium, so this calculator always reports both contributions.
Use Target → Dose, choose phosphate, and select monopotassium phosphate. The calculator determines the dry dose and also reports the potassium added.
Yes. Monopotassium phosphate supplies phosphate and potassium. Both are included in every result.
One gram of pure magnesium sulfate heptahydrate in 100 liters adds about 0.99 mg/L magnesium, plus sulfate.
MgSO4·7H2O contains seven waters of hydration, so each gram contains less magnesium and sulfate than the same mass of anhydrous MgSO4. Select the exact compound on the package.
Choose Stock Solution → Build recipe, enter the aquarium, bottle and dose volumes, then choose the nutrient target and compatible compound. The result gives the amount to add to the full bottle.
Use actual water volume when known. Substrate, hardscape, equipment and air space usually make it lower than the nominal tank volume.
In dilute freshwater nutrient solutions, mg/L and ppm are commonly treated as approximately equivalent.
