Estimative Index (EI)

Estimative Index (EI) is a simple method of dosing fertilizers to a planted tank. This method was originally coined by Tom Barr. The basic idea involves dosing excessamount of nutrients than plants need throughout the week and then resetting the aquarium by doing 50% water change on 7th day. After that repeat the process again.

Plants require:

  • Macronutrients - Nitrate (NO3), Phosphate (PO4) and Potassium (K) and
  • Micronutrients - Iron (Fe), manganese, boron, copper, chlorine, zinc, molybdenum and other elements that are part of Trace Mix ( Rexolin ).

Macronutrients are required in large amount compared to Micronutrients which are required in smaller amount. That is the reason they are names Macros and Micros.Extra iron can be also added if required.

Here are the nutrient target ranges in parts per million (ppm) for EI Dosing:

  • Nitrate (NO3) range 20-30 ppm
  • Potassium (K) range 15-30 ppm
  • Phosphate (PO4) range 2-6 ppmIron
  • (Fe) range 0.5-1ppm (or higher in some cases)

    Dosing

    Dosing dry fertilizers is very easy using measuring spoons. You can add rough teaspoon measurement of the dry fertilizers straight into the aquarium or can mix them separately with aquarium water and then add to the aquarium. Sometimes its hard to measure 1/16 or 1/32 using normal teaspoon so I do recommend you to use kitchen measuring spoons or another way is to make EI solutions so its easy to dose smaller tanks..

    35-70 Litre Aquariums

    • +/- 1/8 tsp KNO3 (N) 3x a week
    • +/- 1/32 tsp KH2PO4 (P) 3x a week
    • +/- 1/32 tsp Trace Elements 3x a week
    • 50% weekly water change

    70-150 Litre Aquariums

    • +/- ¼ tsp KN03 3x a week
    • +/- 1/16 tsp KH2P04 3x a week
    • +/- 1/16 tsp Trace Elements 3x a week
    • 50% weekly water change

    150-225 Litre Aquariums

    • +/- 1/2 tsp KN03 3x a week
    • +/- 1/8 tsp KH2P04 3x a week
    • +/- 1/8 tsp Trace Elements 3x a week
    • 50% weekly water change

    225 – 300 Litre Aquariums

    • +/- 3/4 tsp KN03 3x a week
    • +/- 3/16 tsp KH2P04 3x a week
    • +/- ¼ tsp Trace 3x a week
    • 50% weekly water change

    300 - 475 Litre Aquariums

    • +/- 1 1/2 tsp KN03 3x a week
    • +/- ½ tsp KH2P04 3x a week
    • +/- ½ tsp Trace 3x a week
    • 50% weekly water change

    What you will need from our store to get ready with EI:


      • Dec 05, 2017
      • Category: News
      • Comments: 2
      2 Comments
      Brent December 13, 2017

      Absolutely awesome info for someone like me that’s always looking for better ways to keep my plants looking good.
      Thanks Jag

      Jagdeep Singh January 05, 2018

      Thanks for liking the post and we will have more cool contents on our website to share with our awesome customers / friends.

      Cheers, Jag

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