2Hr Aquarist APT Zero (APT1) Planted Aquarium Fertilizer

2Hr Aquarist APT Zero (APT1) – Lean All-in-One Planted Aquarium Fertilizer

2Hr Aquarist APT Zero, now known as 2Hr Aquarist APT1, is a comprehensive planted aquarium fertilizer specially formulated for new aquariums and tanks with more fish and fewer plants. It provides essential plant nutrition without adding nitrates or phosphates, making it particularly useful where fish food and livestock waste already contribute nitrogen and phosphorus to the aquarium.

APT1 follows the nutrient philosophy of APT3 while excluding added nitrate and phosphate. This allows aquarists to provide potassium, magnesium, iron and essential trace nutrients while maintaining a leaner nutrient regime. The manufacturer recommends APT1 for new aquasoil tanks during their first 1–3 months and for long-term use in established aquariums with comparatively higher fish loads.

Complete Nutrition Without Added Nitrates & Phosphates

The 2Hr Aquarist APT1 fertilizer is formulated to complement aquariums where fish feeding and organic waste already provide meaningful amounts of nitrogen and phosphorus.

According to the current manufacturer’s guaranteed analysis, APT1 contains:

• Soluble Potash (K₂O): 5.5%
• Magnesium (Mg): 0.85%
• Iron (Fe): 0.1%
• Chelated iron
• Essential trace nutrients

The current formula uses potassium, magnesium and multiple chelated forms of iron to provide plant nutrition across a range of planted aquarium conditions.

Ideal for Tanks with More Fish & Fewer Plants

2Hr Aquarist APT Zero / APT1 is particularly suitable for:

• New planted aquariums
• New aquasoil tanks
• Aquariums with higher fish load
• Tanks with fewer plants
• Sparsely planted aquariums
• Aquariums where nitrate and phosphate are already supplied through fish feeding and waste
• Aquarists looking for a leaner fertilization approach

The manufacturer currently recommends APT1 as the starting fertilizer for new aquariums during approximately the first 1–3 months, particularly when aquasoil is used.

Why No Added Nitrate or Phosphate?

Fish food and livestock waste naturally contribute nitrogen and phosphorus to aquarium water.

In tanks with relatively more fish and fewer plants, adding substantial additional nitrate and phosphate may not always be necessary.

APT1 therefore provides other important nutrients while containing no added nitrate or phosphate, allowing the aquarist to maintain a leaner nutrient regime.

As plant mass increases and nutrient consumption becomes greater, an aquarium may eventually benefit from moving to APT3 / APT Complete, which provides comprehensive macro, micro and trace nutrition including nitrogen and phosphorus.

APT Zero / APT1 Dosage

Standard Dosage: 3ml per 100 litres daily.

APT1 can be dosed at any convenient time of day. According to 2Hr Aquarist, consistent dosing is more important than the particular time of dosing.

For aquariums without CO₂ injection or tanks containing mostly slow-growing or shade plants, nutrient requirements may be lower and dosage can be adjusted according to the aquarium’s requirements.

When switching from a substantially different fertilizer system, introducing APT1 progressively can help reduce the possibility of temporary instability. The manufacturer suggests transitioning incrementally over approximately two weeks.

Which 2Hr Aquarist APT Fertilizer Should You Choose?

Have a mature aquarium with more plants and fewer fish? Consider 2Hr Aquarist APT Complete (APT3) for comprehensive macro, micro and trace nutrition.

For heavily planted aquariums following an EI-style nutrient approach, explore 2Hr Aquarist APT Estimative Index (APTe)

APT1 / APT Zero
Best suited to new tanks or aquariums with more fish and fewer plants. It provides comprehensive nutrition without added nitrate and phosphate.

APT3 / APT Complete
Designed for established aquariums with more plants and fewer fish, providing comprehensive macro, micro and trace nutrition.

APTe / APT Estimative Index
Designed for heavily planted aquariums, particularly aquarists following an Estimative Index style nutrient approach.

This distinction closely follows the manufacturer’s current APT selection guidance.

When Should You Move from APT1 to APT3?

The manufacturer’s current advice gives us a useful practical guideline.

If aquarium nitrate continues increasing from week to week, the fish load may already be providing substantial nitrogen, making APT1 the appropriate choice.

If nitrate remains very low or reaches zero as plant mass and nutrient consumption increase, consider moving to APT3 / APT Complete.

Available Sizes

2Hr Aquarist APT Zero (APT1) is available in:

200ml | 300ml | 500ml | 1000ml

Select the required bottle size according to your aquarium volume and dosing requirements.

Discover more 2Hr Aquarist Fertilizers & Planted Aquarium Products for planted aquarium and aquascaping needs.

For the latest formulation details, dosing recommendations and technical information, visit the official 2Hr Aquarist APT1 Product Guide.