Estimative Strategy Questions?


Junior Poster
Feb 3, 2010
I paid and got your Guide for Dosing. I have a few small questions after reading it. The first is about the Estimative Index Strategy. It talks about how Tom Barr's describes a typical 20 gallon tank for doing. Below that their is a chart the shows a typical Dosing Routine. Is that for a 20 gallon tank? If so I have a 100 gallon aquarium. Would I use 5 times the amount that he used since my tank is 5 times as large as a 20 gallon?

For example. The cart said 1 /4 teaspoon of KNO3 3-4x a week (every other day)

So I would use 1 1/4 teaspoon for my 100 gallon tank?

Now would that be adding dry fertilizers to the tank or a mixing bowl or do you make it into a liquid with the ratio of 1 teaspoon per 500ml and then use 1 1/4 teaspoon of that liquid fertilizer? Once again we are talking about the Estimative Index Strategy.


Lifetime Charter Member
Lifetime Member
Jan 5, 2009
Washington, DC

Hi Qualityguppies,

Simply, some people dump them directly into the tank. Others premix them with a little tank water before they dump them into the tank. Some decide to make stock solutions because smaller tanks require measurements of 1/32 of a teaspoon and we (yes me) have an aversion to teaspoons that small. As far as I know all the methods work equally well. Start with the dry methods first. As your aversion to teaspoons develops try making stock solutions. EI guidelines are for tanks with non-limiting CO2 (30ppm), mid to high light and lots of plants. It is meant to provide non-limiting levels of nutrients for plants under those conditions. Less light, fewer plants, fish load, CO2 can all change the demand. EI is someplace to start, given the number of variables, but is adjusted to your circumstances. What is already in your tap water? What lighting do you have? Are you using CO2? What is the size of the bio-mass? Those kinds of questions. Here are a few places to start reading up on EI that provide more information to get you started.

Good luck and welcome to the Barr Report.