Aquarium dosing calculator
Labels give a dose per 10, 40 or 50 gallons; your tank is something else. Enter the label dose and the volume you are treating.
The formula
your dose = label dose × (your volume ÷ label volume). If a conditioner says 5 mL per 50 gallons and you are treating 29 gallons, the dose is 5 × 29 ÷ 50 = 2.9 mL. The calculator converts between US gallons and liters, so a label written in liters works for a tank measured in gallons.
Which volume to treat
- Water conditioner during water changes: dose for the new water you add. Many keepers dose for the whole tank to be safe — most conditioners are harmless at a few times the label dose — but check the label.
- Medication and fertilizer: dose for the actual water volume, not the tank's nominal size. A "55-gallon" tank with gravel and rock often holds 45 gallons; dosing for 55 is a 20% overdose. Use the volume calculator with glass, water level and substrate to find it.
- Remove carbon from the filter when medicating, unless the label says otherwise.
Small doses
For nano tanks the dose can be a fraction of a milliliter. A 1 mL oral syringe from a pharmacy measures 0.1 mL steps. Teaspoons are 4.93 mL and a typical dropper delivers about 20 drops per mL, but droppers vary — use a syringe for medication.
FAQ
How much water conditioner for a 10-gallon tank?
With a label dose of 5 mL per 50 gallons, 1 mL treats 10 gallons. With 5 mL per 10 gallons, use 5 mL.
Should I dose for the whole tank or just new water?
Dose dechlorinator at least for the new water; medication and fertilizer for the actual water volume of the tank.
How many mL is a teaspoon?
One US teaspoon is 4.93 mL, usually rounded to 5 mL.