Tools

Advanced Nutrient Calculator

Mix your ideal nutrient solution

This calculator helps you design custom nutrient solutions by combining various compounds to achieve specific ion concentrations. You can enter either the compound concentration in µM or the cation/anion concentration in mg/L — the other fields will update automatically. The tool calculates the resulting ion profile, displays real-time totals and balance indicators, and visualizes the distribution of ions in your solution.

It’s especially useful for experimental setups where you know the target ion concentrations but need to determine the most efficient or cost-effective combination of compounds to achieve them. Whether you're optimizing for nutrient ratios, purity, or economic feasibility, this tool helps you explore and refine your solution design with precision.

Clicking on the name of the anion (like NO₃⁻) in the last column will highlight all its instances (i.e., all compounds that can be used to add it).
Clicking on the name of the compound in the "Formula" column will automatically take you to the "Stock solution designer" page, where your values will be pre-filled.
Below the table you'll find a "Shareable link", which contains all your input data and can be shared or used for future reference.

➤ Use <test values> to try out how it works.

Compound				Cation		Anion
Formula	purity	[µM]	[mg/ℓ]	+	[mg/ℓ]	[mg/ℓ]	–
NH₄NO₃				NH₄⁺			NO₃⁻
H₃PO₄ (85%)				H⁺			H₂PO₄⁻
KH₂PO₄				K⁺			H₂PO₄⁻
KCl				K⁺			Cl⁻
KHCO₃				K⁺			HCO₃⁻
KNO₃				K⁺			NO₃⁻
K₂SO₄				K⁺			SO₄²⁻
CaCl₂*2H₂O				Ca²⁺			Cl⁻
CaCO₃				Ca²⁺			CO₃²⁻
Ca(NO₃)₂*4H₂O				Ca²⁺			NO₃⁻
CaSO₄*2H₂O				Ca²⁺			SO₄²⁻
MgCl₂*6H₂O				Mg²⁺			Cl⁻
Mg(NO₃)₂*6H₂O				Mg²⁺			NO₃⁻
MgSO₄*7H₂O				Mg²⁺			SO₄²⁻
NaCl				Na⁺			Cl⁻
NaHCO₃				Na⁺			HCO₃⁻
NaNO₃				Na⁺			NO₃⁻

Shareable link: tools-nutricalc2

Cations

Anions

Cations (mg/ℓ)

Anions (mg/ℓ)

PHREEQC ready-to-use input block

You can copy and paste the block below directly into the PHREEQC program → see this article for details.

CO₂(aq): mg/ℓ

SOLUTION 1 Planted Tank with solid Calcite and CO₂
    temp       25
    pH         5.5            # give initial pH; actual pH will be computed
    units      umol/L         # all units need to be converted to µmol/ℓ
    Na         
    K          
    Ca         
    Mg         
    N(-3)         as NH4
    N(+5)         as NO3
    P              as PO4-3
    S(6)          as SO4-2
    Cl             charge    # let PHREEQC tweak Cl⁻ to balance the solution
    C(4)          as HCO3-
END

EQUILIBRIUM_PHASES
    CO2(g)               # equivalent to  mg/ℓ CO₂
    Calcite 0          #  µM of solid calcite =  mM =  M ()
END

USE SOLUTION 1
USE EQUILIBRIUM_PHASES 1
SELECTED_OUTPUT
    -file selected_output.txt
    -reset false
    -high_precision true
    -totals N P K Ca Mg Na Cl S C
    -molalities NH4+ NH3 N2 NO2- NO3- H2PO4- HPO4-2 PO4-3 HCO3- CO3-2 CO2 Ca+2 Mg+2 Na+ K+ Cl- SO4-2
    -equilibrium_phases Calcite CO2(g)
    -saturation_indices Calcite CO2(g)
    -ionic_strength true
    -charge_balance true
    -pH true
    -pe true
END