Turn a target EC or PPM reading and your reservoir volume into grams of each nutrient salt, using a general three-part reference ratio.
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How to Use the Hydroponic Nutrient Calculator
Choose how you measure strength (EC in mS/cm, or PPM on the 500 or 700 scale), enter your target reading and the reservoir volume in litres, then press Calculate. The tool returns the grams of each nutrient part to weigh out. Use Clear to reset the form.
General reference ratio
The split below is a widely used general dry-salt blend for leafy crops. It is a general reference ratio, not any brand's formula — always follow the label and mixing order of the product you actually use.
Nutrient part
Share of total weight
Calcium nitrate
40%
Complete NPK fertilizer (with micronutrients)
40%
Epsom salt (magnesium sulfate)
20%
What the result means
The calculator assumes about 0.8 g of dry salts per litre raises EC by roughly 1.0 mS/cm — a practical average, not a lab value.
PPM is converted to EC with the 500 scale (PPM = EC × 500) or the 700 scale (PPM = EC × 700); pick the one your meter uses.
Dissolve calcium nitrate separately from the sulfate and phosphate parts to avoid precipitation.
Start slightly below the target, then top up, because water and base nutrients already carry some EC.
Features
Converts a target EC or PPM into grams of each nutrient salt
Works for any reservoir size from 1 to 1000 litres
Shows the general three-part reference ratio directly on the page
Works on desktop, tablet and mobile with no sign-up
All processing runs locally in your browser. Your data is not uploaded to any server.