Aquarium Fertilizer Dosing Calculator
Estimate what your fertilizer doses add and how water changes affect nutrient levels over time.
Aquarium, water changes, and fertilizer products
Add fertilizer rows and calculate the weekly nutrient profile.
Plan details and reference bands
Calculate to get a dosing interpretation.
Nutrient contributions
Tap water plus one fertilizer dose, before later doses or water changes.
| Nutrient | Fertilizer addition | Tap water | Modeled total |
|---|---|---|---|
| Nitrate (NO3) | 0.00 mg/L | 0.00 mg/L | 0.00 mg/L |
| Phosphate (PO4) | 0.00 mg/L | 0.00 mg/L | 0.00 mg/L |
| Potassium (K) | 0.00 mg/L | 0.00 mg/L | 0.00 mg/L |
| Iron (Fe) | 0.00 mg/L | 0.00 mg/L | 0.00 mg/L |
| Calcium (Ca) | 0.00 mg/L | 0.00 mg/L | 0.00 mg/L |
| Magnesium (Mg) | 0.00 mg/L | 0.00 mg/L | 0.00 mg/L |
| Urea | 0.00 mg/L | 0.00 mg/L | 0.00 mg/L |
| Ammonium (NH4) | 0.00 mg/L | 0.00 mg/L | 0.00 mg/L |
Nutrients over time
Solid lines include fertilizer dosing; dashed lines represent tap-water-only nutrients.
Save or share this dosing plan
Apply this result to your aquarium, save it for later, or export a clean summary.
Aquarium Fertilizer Calculator FAQ
Which fertilizer products does this calculator use?
It uses the existing AquariumLesson fertilizer product list with the same stored nutrient values used across the site.
How are nutrient additions calculated?
Each selected product contributes its listed nutrient values according to dose and aquarium volume. Known tap-water values are added separately. The result is a modeled contribution, not a measurement of aquarium nutrient levels.
Why does the chart move up and down?
The chart models repeated dosing and water changes. Dosing raises the nutrient level, while water changes dilute the current level and replace part of it with tap water concentration.
Can I combine liquid and dry fertilizers?
Yes. The product list contains ml and g units, and each fertilizer row keeps the selected product unit when calculating its contribution.
Save this result. Pick up where you left off.
Create a free account to save this result in Saved Calculations and reopen it later.
My Aquariums adds insights and care tools for your own setup. Advanced AI assistance is available with PRO.