How often should I dose fertilizer?

It depends on density: few plants 1x/week, medium 2x, densely planted 3x or daily in small doses. Ideally after the water change.

Can I use fertilizer in a discus tank?

Yes, quality aquarium fertilizers are safe for fish. Avoid overdosing and products with high copper if you keep shrimp or snails.

How do I know if I'm dosing too much?

Algae (especially on the glass and leaves), cloudy water or plants that don't respond are signs. Reduce the dose and increase water changes.

Do I need CO₂ for fertilizer to work?

Not for easy plants (Anubias, ferns, Cryptocoryne). For demanding, fast-growing plants, CO₂ helps them use the fertilizer efficiently.

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Fertilizer dosing calculator for planted aquariums

Not sure how many ml of fertilizer to add to your planted discus tank? Choose the volume, plant density and fertilizer type, and the calculator estimates the weekly dose and the amount per application.

Fertilizer dosing calculator

How many ml of fertilizer for your planted tank

Tank volume (L)

Plant density

Fertilizer type

Enter the tank volume to calculate the dose.

Indicative, calibrated for typical all-in-one fertilizers (e.g. Tropica, APT). Your manufacturer's instructions remain the reference. Discus prefer low-bioload tanks — don't over-fertilize.

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Frequently asked questions

Save your tank and stop recalculating every timeNEW

Create your tank in “My Aquarium” and your parameters, volume and tasks stay saved. You also get free email reminders.

Open My Aquarium

Other useful calculators

📐Tank volume calculator→🐟Stocking calculator→💧Water change calculator→🍤Discus food calculator→💶Monthly cost calculator→💊Treatment calculator→

For the planted tank

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