With the 2HR Aquarist APT-EI, 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.

An overview of the EI methodology can be foundhere.

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

EI aims to dose all nutrients in excess through heavily dousing the water column with nutrients. Levels are normalised at the end of each week with large (50%) water changes. The aim is to provide plants with non-limiting amounts of nutrients.

A weekly cumulative dose of nutrients according to EI would be around:
NO3 – up to 20 – 30ppm
PO4 – up to 5 – 7ppm
K – up to 20 – 30ppm
Fe/traces – up to 0.5 – 1ppm