Plant care calculator
Aquarium Plant Fertilizer Dosage Calculator
Calculate exact macro and micro fertilizer doses for your planted aquarium based on tank volume, plant density, CO2 system, and dosing strategy.
Quick Answer
This calculator is for planted aquariums, not ordinary houseplant pots. It scales fertilizer dosage by aquarium water volume, dosing strategy, plant density, and CO2 setup so aquatic plants receive nutrients without pushing unnecessary algae risk.
Enter your details
Enter the labeled values below. Results appear without leaving this page.
Recommended Output
Method
Weekly macro and micro targets are calculated from actual water volume, then scaled by dosing strategy, plant density, and CO2 setup. The model uses separate base rates for EI, PPS-Pro, and low-tech systems, then multiplies them by density and carbon-demand factors to match nutrient uptake pressure.
Reference Table
Static Aquarium Plant Fertilizer Dosage Calculator Reference
Visible baseline values
These baseline ratios and decision rules are included directly in the page so visitors can review core guidance before using the interactive calculator.
| Scenario | Baseline Rule | Safety Note |
|---|---|---|
| EI planted aquarium dosing | Macro 5 ml per 20 gal/week and micro 5 ml per 20 gal/week before plant-density and CO2 adjustment. | High-energy method; pair with stable CO2, consistent light, and 40-50% weekly water changes. |
| PPS-style lean dosing | Macro 7 ml per 10 gal/week and micro 7 ml per 10 gal/week before density and CO2 adjustment. | Dose smaller amounts consistently and watch algae response for 2 weeks. |
| Low-tech aquarium dosing | Macro 2 ml per 20 gal/week and micro 1 ml per 20 gal/week before density adjustment. | Best for low-light tanks without pressurized CO2. |
Formula summary: Formula pattern: weekly_dose_ml = tank_volume_gal x strategy_base_rate x plant_density_multiplier x co2_multiplier. Macro and micro channels use independent base rates, then output a practical schedule with algae-risk caution when energy inputs are high.
The Problem
Planted aquarium dosing is easy to over- or under-estimate because nutrient demand changes with water volume, plant mass, light intensity, and CO2 availability.
When to Use This Tool
Use this calculator when setting up a planted aquarium, changing fertilizer methods, increasing plant density, adding CO2, or troubleshooting algae and slow aquatic plant growth.
Who is this for?
- Planted aquarium keepers comparing EI, PPS-Pro, and low-tech fertilizer routines
- Aquascapers adjusting nutrient dosing for plant density and CO2 availability
About this calculator
Aquarium plant fertilizer dosing depends on water volume, light energy, plant density, and CO2 availability. This calculator gives a practical baseline for planted tanks.
How to Use
- Enter the aquarium's real water volume in gallons.
- Choose the dosing strategy that best matches your tank: EI, PPS-Pro, or low-tech dosing.
- Select plant density and CO2 setup to adjust the macro and micro dose estimate.
Why Aquarium Volume Matters
Aquatic fertilizer is diluted through the entire water column. A 20 gallon planted tank and a 75 gallon planted tank need different total doses even when they use the same fertilizer method. CO2 and plant density change uptake speed, while low-tech tanks usually need leaner dosing to reduce algae pressure.
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Aquarium Fertilizer Dosing Methods Compared
| Method | Best For | Water Change Need | Difficulty |
|---|---|---|---|
| Estimative Index (EI) | High light, CO2-injected planted tanks | Weekly 40-50% | Moderate |
| PPS-Pro | Lean daily dosing and stable planted tanks | Smaller regular changes | Moderate |
| Low-tech dosing | Low light tanks without injected CO2 | Routine maintenance | Easy |
Troubleshooting Guide
1 Algae increases after dosing
Cause: The tank may have too much light, unstable CO2, excess nutrients for the plant mass, or inconsistent water changes.
Reduce light intensity or duration first, keep CO2 stable if injected, maintain regular water changes, and lower dosing strength until plant growth catches up.
Glossary of Terms
- Transpiration
- The process of water movement through a plant and its evaporation from aerial parts.
- Photoperiod
- The period of time each day during which an organism receives illumination.
Scientific References
- Aquatic Plant Fertilization — Aquatic Gardeners Association
- Nutrient Dosing in Planted Aquaria — The Aquarium Wiki