2Hr Aquarist APT Estimative Index

Designed to exceed the maximum estimate of plant-growth requirements, the famous nutrient dosing approach pioneered by Tom Barr is now available in a ready-to-use concentrate that removes the guesswork from trying to recreate this powerful and sometimes elusive formula.

The 2Hr Aquarist APT Estimative Index fertilizer saturates the water heavily with NPK, Mg, Fe, and Traces, removing all nutrient deficiencies from the equation. This allows the aquarist to focus on tuning light, CO2 and other variables. An overview of the EI methodology can be found here.

Dose 5ml per 100L 3 times per week or 2ml per 100L daily. FAQ here.

Each 5ml per 100L dose adds 6ppm Potassium (K), 6ppm Nitrogen (NO3), 1.5ppm Phosphorus (PO4), 0.16ppm Iron (Fe), and additional amounts of Boron (B), Copper (Cu), Magnesium (Mg), Manganese (Mn), Molybdenum (Mo) and Zinc (Zn).

Should you use APT Complete, APT Zero or Estimative Index?

APT Series Usage Guide


When performance matters

Above: a fast-growing 'farm tank' using APT Complete. Aquasoil is used as substrate, paired with additional root tabs for faster growth of 'blood vomit' and the red Eriocaulon quinquangulare.

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Above: a slower-growing nature-style diorama using APT Complete. 

Capstone Ratio