Scape
Math
Metric
US
Fertilizer dosing calculator (dry salts)
Tank water volume
L
Fertilizer
Potassium nitrate (KNO₃)
Monopotassium phosphate (KH₂PO₄)
Potassium sulfate (K₂SO₄)
Epsom salt (MgSO₄·7H₂O)
Trace mix / chelated iron (enter % from label)
Element % on the label
e.g. iron (Fe) %
%
Grams → ppm
Target ppm → grams
Stock solution
Amount dosed
g
Raise which nutrient
Raise by
ppm
Salt dissolved
g
Final solution volume
mL
Dose
mL
Result
–
Tank water volume
L
NO₃ per dose
ppm
PO₄ per dose
ppm
Total K per dose
ppm
Mg per dose
if your water is soft
ppm
Doses per week
Weekly water change
%
Salt
Per dose
Supplies
Free calculator by
ScapeMath
. Method, worked examples and sources on the full page.