Free Hydroponics Tools & Calculators

Quick, practical calculators for nutrient mixing, EC/PPM, reservoir volume, lighting and repeatable pH adjustments.

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EC to PPM Calculator

Convert electrical conductivity (EC) to the common 500 or 700 PPM scales.

EC (mS/cm)

PPM scale

Enter your EC aboveExample: EC 1.6 = 800 ppm on the 500 scale.

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Work out how many millilitres of nutrient concentrate to add to a reservoir.

Reservoir volume (L)

Dose (ml per L)

Enter your reservoir and label doseAlways follow the nutrient manufacturer's instructions and adjust for your crop and water.

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Estimate the water capacity of a rectangular or cylindrical reservoir.

Reservoir shape

Length (cm)

Width (cm)

Water depth (cm)

Enter the inside dimensionsThe result is an estimate; leave suitable headspace rather than filling to the rim.

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Estimate Daily Light Integral from average PPFD and the number of light-hours per day.

Average PPFD (µmol/m²/s)

Light hours / day

Enter PPFD and light hoursDLI = PPFD × hours × 0.0036. Use an average canopy PPFD for a more useful estimate.

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Scale a small, previously tested pH-up/down dose to a larger reservoir.

Test water volume (L)

Test dose used (ml)

Full reservoir volume (L)

Use a small test sample firstThis scales your own tested dose; it does not guess acid/base strength or buffering.

Add pH adjuster gradually, mix thoroughly and re-test. Different water and nutrient solutions can respond very differently.