A spare tent and a couple of reservoirs can out-produce a backyard plot several times over — basil sold to restaurants, strawberries in a garage through winter, lettuce turning over every three weeks. Then the plants yellow, curl, and stall, and the bottle label doesn't tell you why.
The label assumes distilled water; yours already has calcium and alkalinity in it. It never warns you that calcium and sulfate in one stock tank turn expensive nutrients into sludge, or that iron quietly stops working above pH 6.5. None of this is hard. It's just invisible, until something dies.
Hydroponicity is the nutrient calculator built for side-hustle growers. Tell it your water, your salts, and what you're growing, and it solves the exact grams of each fertilizer — corrected for your tap, checked for precipitation, matched to your pH. You get a number you can trust and the reason it's right.
No account needed for the free calculators. The engine keeps the full math intact — the surface just hides what you don't need day to day.
Each tool solves one real problem and lives at its own URL. No sign-up to try them.
Convert between EC and ppm on any meter scale (500 / 640 / 700), with 25 °C temperature correction.
Targets “ec to ppm hydroponics”
Turn a guaranteed-analysis N-P-K label (oxide form) into the elemental percentages every ppm calc needs.
Targets “convert P2O5 to P”
The real multi-salt engine: enter target ppm, get grams per fertilizer and a solved ion balance. One free solve.
Targets “hydroponic nutrient calculator”
Not a stack of single-salt calculators — a constrained weighted least-squares solve across every fertilizer at once, so one salt's contribution to K doesn't wreck your Mg.
Every system carries its own state: active recipe, water source, last reading. Log an EC/pH reading and it's compared against that system's target automatically.
The full engine — source-water correction, ion balance, EC estimate, pH dosing — stays intact underneath. The UI exposes only what a side-hustle grower uses day to day.
A missed EC or pH warning is a real dosing error, so safety warnings and approximation caveats are always free and always visible — regardless of tier. Every result traces back to its inputs, so you can verify the math before you weigh anything out.
Keep calcium and sulfate in separate stock tanks — they precipitate as gypsum when concentrated.
Acquisition hooks — the commodity converters, plus one real solve.
Funnel position, not math complexity.
Start freeThe full multi-salt recipe solver bundle, with persistence.
The paid conversion moment.
Go ProReservoir management & stock-injector scaling for recirculating setups.
Subscription if you recirculate; otherwise a one-time unlock.
Add to Pro