APT 1 is an all-in-one liquid fertilizer for aquariums with more fish than plants, and for new aquariums with aquasoil. The formula replicates the full balanced profile of APT 3 but without nitrates and phosphates — because in fish-heavy tanks, these nutrients are already supplied in sufficient quantities through fish food and waste. The result is maximum algae control combined with complete micronutrient delivery for healthy plant growth.

APT 1 is 3 times more concentrated than conventional fertilizers (in total soluble elements per ml), with components up to 50 times more bioavailable across a wide range of pH values.

Who is APT 1 for?

• Aquariums with more fish than plants
• New aquariums (first 1–3 months) with aquasoil
• Low-tech tanks without CO₂ injection
• Tanks prone to algae due to excess nutrients

How does it work?

APT 1 supplies potassium, magnesium, iron, and trace elements (B, Cu, Mn, Mo, Zn) without adding nitrogen or phosphorus. Plants use the nutrients already available in the aquarium from fish waste and the substrate, while the risk of nutrient oversaturation — the primary driver of algae growth — is kept to a minimum.

Dosing

• 3 ml per 100 L daily
• Recommended water change: 30% weekly
• 300 ml (with pump) ≈ 3 months for a 115 L tank

Guaranteed analysis

• NPK: 0-0-7 (+1.4)
• Soluble Potash (K₂O): 7%
• Magnesium oxide (MgO): 1.4%
• Iron (Fe, chelated EDTA/DTPA/EDDHA): 0.09%
• Trace elements: B, Cu, Mn, Mo, Zn
• Safe for shrimp and sensitive fish

When to switch to APT 3?

After the first 3 months in a new aquarium, or once your tank has more plants than fish, consider transitioning to APT 3 — the full NPK fertilizer in the series.

Which APT fertilizer is right for you?

Frequently Asked Questions

What is APT 1 used for?

APT 1 is a liquid fertilizer for aquariums where nitrates and phosphates are already present from fish waste or a nutrient-rich substrate. It provides potassium, magnesium, iron, and trace elements without adding nitrogen or phosphorus.

Is APT 1 safe for shrimp?

Yes, APT 1 is safe for shrimp and sensitive fish when used at the recommended dosage.

When should I switch from APT 1 to APT 3?

After the first 1–3 months in a new aquarium with aquasoil, or when plants outnumber fish in your tank.

Can APT 1 be used in a tank without CO₂?

Yes. APT 1 is well-suited for low-tech aquariums without CO₂ injection.

Does APT 1 help control algae?

Yes. By withholding nitrates and phosphates, APT 1 reduces the risk of algae growth caused by excess nutrients — a common issue in fish-heavy or newly established tanks.

What is the difference between APT 1 and APT 3?

APT 1 contains no nitrates or phosphates and is designed for fish-heavy or new tanks. APT 3 provides full NPK nutrition and is designed for plant-heavy aquariums where the substrate alone cannot supply sufficient nitrogen and phosphorus.