How much Easy Green for a 5 gallon tank?

Aquarium Co-op's directions are 1 mL per 10 gallons, once a week for low-light tanks or twice a week for medium light, so a 5 gallon tank takes 0.5 mL per dose.

How much Seachem Flourish per gallon?

Seachem directs 5 mL (one capful) per 250 L (60 US gallons) once or twice a week, which is about 0.08 mL per gallon.

Are all-in-one fertilizers the same strength?

No. On the labels we read, Thrive lists 9.7% K2O and Easy Green 9.21%, while Flourish lists 0.37% K2O and is mostly trace elements. Compare the ppm per dose, not the bottle.

Entry 05Liquid ferts

Liquid fertilizer, dosed to the label

Choose the bottle you have. You get the maker's own dose for your water volume, and what that dose adds in ppm, worked out from the guaranteed analysis printed on the label.

Last updatedOct 19, 2026

Dosesfrom each maker's directions, read Oct 19, 2026

Units

Lgal

Fertilizer

Product

Tank

Water volume example (in liters)After substrate and rock.

Work out your water volume

Label dose for your tank

–

–per week at the label's frequency

What one dose adds
Nutrient	Label, % w/w	Per dose	Per week

The six labels

Directions as printed by each maker
Product	Directions	Frequency	Source
Seachem FlourishTrace-focused (very little N, P, K)	Use 1 capful (5 mL) for each 250 L (60 US gallons) once or twice a week.	1–2× a week	Seachem
Tropica Premium NutritionNo nitrogen or phosphorus	6 mL (3 pumps) per 50 L water per week.	weekly, at the water change	Tropica
Tropica Specialised NutritionAll-in-one with N and P	6 mL (3 pumps) per 50 L water weekly.	weekly, at the water change	Tropica
Aquarium Co-op Easy GreenAll-in-one with N and P	1 mL per 10 gallons (500 mL bottle cap); once a week for low light, twice for medium light.	1× a week (low light) or 2× (medium)	Aquarium Co-op
NilocG ThriveAll-in-one with N and P	1 mL per 5 gallons, 1–3 times per week.	1–3× a week	NilocG Aquatics
2Hr Aquarist APT CompleteAll-in-one with N and P	3 mL per 100 L per day.	daily	2Hr Aquarist

From label percent to ppm

Labels give a guaranteed analysis as a percent by weight. To turn a dose into ppm, the calculator multiplies the milliliters by the weight of a milliliter, by the percent, and divides by your water in liters. No label we read gives the solution's density, so we assume 1 mL weighs 1.00 g. Fertilizer solutions are denser than water, so the true ppm are somewhat higher than shown.

US labels report phosphorus as P₂O₅ and potassium as K₂O. We convert them to the PO₄ and K that test kits read, using factors computed from atomic weights: 1 part P₂O₅ is 1.338 parts PO₄, and 1 part K₂O is 0.830 parts K. Nitrogen is shown as N, as labeled. Tropica's declarations already give P and K.

Compare by ppm

Bottles that look alike carry very different amounts. Seachem Flourish is mostly trace elements and iron (Seachem¹), while Easy Green (Aquarium Co-op⁴), Thrive (NilocG Aquatics⁵) and APT Complete (2Hr Aquarist⁶) carry nitrogen, phosphorus and potassium too. Tropica sells Premium Nutrition without nitrogen or phosphorus (Tropica²) and Specialised Nutrition with them (Tropica³).

Sources for this page

1Seachem: Flourish: directions and guaranteed analysisRead Oct 19, 2026
2Tropica: Premium Nutrition: dosage and declarationRead Oct 19, 2026
3Tropica: Specialised Nutrition: dosage and declarationRead Oct 19, 2026
4Aquarium Co-op: Easy Green all-in-one fertilizer: directions and analysisRead Oct 19, 2026
5NilocG Aquatics: Thrive all-in-one liquid fertilizer: directions and analysisRead Oct 19, 2026
62Hr Aquarist: APT Complete: instructions and analysisRead Oct 19, 2026

Every figure above traces to one of these. Formulas are on Methods. Found an error? hello@mosspearl.com