🌱 Aquarium Fertilizer Calculator
Calculate precise fertilizer doses for your planted tank based on volume, plant density & fertilizer type
| Tank Type | Nitrate N (ppm) | Phosphate P (ppm) | Potassium K (ppm) | Iron Fe (ppm) |
|---|---|---|---|---|
| Low Tech / No CO2 | 5–10 | 0.1–0.5 | 5–10 | 0.05–0.1 |
| Medium — Moderate Plants | 10–20 | 0.5–1.5 | 10–20 | 0.1–0.3 |
| High Tech / CO2 Injected | 20–40 | 1–3 | 20–30 | 0.3–0.5 |
| EI (Estimative Index) | 20–50 | 3–5 | 20–50 | 0.5–1.0 |
| Walstad / Natural | 5–15 | 0.1–1.0 | 5–15 | 0.05–0.2 |
| Tank Volume | Low Density (mL/dose) | Medium Density (mL/dose) | High Density (mL/dose) | Weekly Total (med) |
|---|---|---|---|---|
| 5 gal / 19 L | 0.5–1 | 1–2 | 2–3 | 3–6 mL |
| 10 gal / 38 L | 1–2 | 2–4 | 4–6 | 6–12 mL |
| 20 gal / 76 L | 2–4 | 4–8 | 8–12 | 12–24 mL |
| 29 gal / 110 L | 3–6 | 6–12 | 12–17 | 18–36 mL |
| 55 gal / 208 L | 5–11 | 11–22 | 22–33 | 33–66 mL |
| 75 gal / 284 L | 7–15 | 15–30 | 30–45 | 45–90 mL |
| 100 gal / 379 L | 10–20 | 20–40 | 40–60 | 60–120 mL |
| 120 gal / 454 L | 12–24 | 24–48 | 48–72 | 72–144 mL |
| Tank Volume | Tabs Needed | Spacing | Replace Every |
|---|---|---|---|
| Up to 10 gal / 38 L | 1–2 tabs | 4–6 in / 10–15 cm | 2–3 months |
| 10–30 gal / 38–114 L | 2–5 tabs | 6 in / 15 cm | 2–3 months |
| 30–55 gal / 114–208 L | 5–10 tabs | 6–8 in / 15–20 cm | 3 months |
| 55–100 gal / 208–379 L | 10–18 tabs | 8 in / 20 cm | 3–4 months |
| 100+ gal / 379+ L | 18+ tabs | 8–10 in / 20–25 cm | 3–4 months |
Live plants truly give life to the aquarium, but they can ruin the whole system if you do not care about their nutrition. They clean the water and pump oxygen in it, what the fishes really enjoy. The problem is, that plants need real food, and only waste from fishes does not work for that.
Many aquariums end with lack of nitrate, potassium, phosphate and different trace minerals, that plants need to stay strong and grow.
How to Feed Aquarium Plants Safely
Plants need big nutrients: nitrogen, phosphorus and potassium, or simply N, P and K, if you like to talk technically. They also need small nutrients, like magnesium and iron, to truly shine. Have some red plants?
A dose of iron does wonders for them. The simplest option is to use all-in-one Aquarium fertilizer, that already mixes everything together. No worry about handling several bottles or counting hard amounts.
Easy Green from Aquarium Co-op leads the market of all-in-one liquids. It fills eveything what aquatic plants need, and will not hurt your fishes, shrimps or snails. Flourish is another solid choice, that many folks like, and it has version Flourish S for aquariums with shrimps.
Seachem products work a bit differently, they focus on precise dosing, what requires you to buy several bottles and follow more detailed steps. Honestly, it soon becomes complex.
Some folks make their own mix using dry salts and clean water, what makes it friendly to the budget. Homemade Aquarium fertilizer costs only four to seven dollars for a bottle of 500 ml, while store liquids reach around twenty to twenty-eight dollars. If you care for several aquariums, making your own saves much money over time.
Here many folks mess up, never pour garden Aquarium fertilizer directly in your aquarium. The mixes are way too strong, and they commonly carry stuff, that does not work for aquatic life. Buildup of copper is a big problem in garden products, what completely destroys shrimps and other creatures.
Aquarium-specific liquids cost sew little and keep everything safe.
That said, not every aquarium truly needs Aquarium fertilizer. Lightly planted setups with lots of fishes and without added CO2 probably will do fine without it. Heavily planted aquariums or those with only some fishes?
They will start to suffer without that extra nitrogen and phosphorus boost. What you ultimately choose depends on the light levels in your aquarium, what plants you grow and what you want to reach. Getting the dose right is key, too much and you riskproblems and trouble with algae.
Many liquid Aquarium fertilizer products claim, that they will not cause bloom of algae. That does not tell the whole picture. Stick with a good aquarium-safe product and follow the directions on the label, and most setups will do well.
