Estimative Index Fertilization Method, EI in Planted Aquarium

An Introduction to EI Method in the Planted Aquarium

What is the EI Method?

The Estimated Index Method (EI Method) is a DIY method of dosing nutrients in an aquarium with the aim of creating conditions for maximum plant growth. The aquarist doses micro and macronutrients multiple times per week to prevent anything running out which would result in plant deficiencies.

“But surely this would result in an algae bloom?” you might ask. This is not the case! When conducted in a high-tech aquarium environment with ample light and CO2 injection, the excess nutrients will be utilised by the plants, outcompeting algae, resulting in a crystal-clear aquarium with healthy plants.

What are Macro and Micronutrients?

Plants require elements found in nature to properly grow and develop, consisting of macronutrients, required in large quantities and micronutrients, required in small quantities

Macronutrients	Micronutrients
Carbon	Iron
Oxygen	Chlorine
Hydrogen	Manganese
Nitrogen	Zinc
Phosphate	Copper
Potassium	Boron
Sulphur	Molybdenum
Calcium	Cobalt (optional)
Magnesium	Nickel (optional)

Preparing the Nutrients

A key feature of the EI method is accurate nutrient dosing. For complete control over the nutrients entering your aquarium is advised to make your own nutrient solutions using dry fertilisers which can be easily purchased from our online store. Dry fertilisers have the added benefit of being much cheaper than their liquid counterparts.

To make the macronutrient solution measure out four teaspoons of potassium nitrate, one teaspoon of potassium phosphate and 6 teaspoons of magnesium sulphate and add to a dosing bottle. Add 500ml of pre-boiled and cooled water and shake the bottle well. It is important to ensure the water has been boiled to kill any bacteria which could later lead to problems.

Note that not all the macronutrients are included in the solution as many will already be present in ample quantities in the aquarium. For example, carbon is supplied from the CO2 injection and nitrogen will be present in fish waste and excess food.

To make the micronutrient solution measure one teaspoon of trace micronutrients (half dose if use our csm+b sashay) and add to separate dosing bottle. Add 500ml of pre-boiled and cooled water to the bottle and shake the bottle well.

Leave both bottles overnight to ensure all salts are properly dissolved.

Dosing in the EI Method

The EI Method runs on a 7-day cycle. Once the cycle has completed, start again from day 1.

Day 1	add 10ml of the macronutrient solution per 50l (11 gallons) of aquarium water
Day 2	add 10ml of the micronutrient solution per 50l (11 gallons) of aquarium water
Day 3	add 10ml of the macronutrient solution per 50l (11 gallons) of aquarium water
Day 4	add 10ml of the micronutrient solution per 50l (11 gallons) of aquarium water
Day 5	add 10ml of the macronutrient solution per 50l (11 gallons) of aquarium water
Day 6	add 10ml of the micronutrient solution per 50l (11 gallons) of aquarium water
Day 7	perform a 50% water change to remove organic waste which has built up

Common Mistakes to Avoid

Low light, low circulation or low Co2 – the EI method is best suited to high-tech aquarium setups. Insufficient levels of light, water circulation or Co2 injection can lead to an algae bloom as the excess nutrients will not be utilised by the plants

Insufficient water changes – it is important that a 50% water change is completed on the final day to remove excess organic waste. If the water change is not large enough, this can also lead to an algae bloom

Not enough plants – plant coverage must be dense for all the excess nutrients to be absorbed. If plants are too sparse, the nutrient dosing will have to be reduced