Tom Barr's Method Of Open Loop Aquarium Plant Fertilization
"Estimative Index"
In the late 1980's aquarium plant fertilization was in its infancy and there was scant information outside the Dupla book. Within years it seemed everybody had a plethora of test kits and "ppm" was the buzzword in aquatic plant fora all over the internet. But, Tom Barr makes a good point that you don't need the feedback from the (almost universally) inaccurate hobby test kits, you can simply change water and dose ad infinitum. Here is Tom's method, often called the "Barr method" (postscript a year later, I gues Tom is shy he refers to this as "estimative index" the term "Barr Method" didn't last), an answer to a question whether or not ones needs to be a chemist to dose aquarium plant fertilizers properly. I quote Tom directly:
Actually no, it's rather easy to determine the nutrient levels and maintain them in one simple step.
No chemistry lesson is needed at all; you can make cereal right? Add enough cereal to fill the bowl, add 2 cups of milk, 2 teaspoons of sugar.
Or I can say add 250 grams of endospermous carbohydrates and 9.5 grams of sucrose to 450mls of bovine lactate exudate.
In a nutshell, you do large weekly water changes (say 50%) each week to prevent anything from building up and and dose 2-4x a week to prevent anything from running out. The names can be whatever you want them to be, but ultimately all you are doing is adding Nitrate, PO4 , K+ (the NPK numbers of bags of fertilizer) and traces.
Farmers do this without chemistry lessons every day.
In this manner you provide a stable range of all the nutrients cheaply, easily and without using a test kit except for CO2(KH/pH).
An example routine for a 20 gal tank with high light:
50% water change
Add: 1/4 teaspoon of KNO3 1/16 or a smidge of KH2PO4 If GH is lower than 3-5 out of the tap, Add SeaChem Equlibrium(1/4 teaspoon)
Next day add 5 ml of trace
Wait one day, add the KNO3/KH2PO4 again, next day add the trace again
Add the KNO3/KH2PO4 Trace again the next day
Water change: repeat ad nauseum.
Dosing 1/4 teaspoon of powered KNO3 = 1.67 grams according to a lab scale with 10 levels averages.
This added to 20 gal= 10-11ppm of NO3. Error is about 1ppm of NO3.
Name one hobby kit that can be that accurate. I'm not aware of any.
We dose excess nutrients in all cases, and there is nothing wrong with that as long as we don't get too far off base; the water changes prevent folks from lousing it up.
You can guess estimate and use the plants as the indicator as you become more skilled and dose less or go longer without water changes. But again, no test kits are needed.
As long as you keep up on dosing and water changes, this is a very simple method and no hassle if you put an automatic water changer on your tank, python style water changer etc or hard plumb a drain/refill.
KH2PO4, KNO3 are very cheap, SeaChem Eq is relatively cheap as well for the once a week dosing. Traces are not too bad at this amount.
Sunday, March 14, 2010
Estimative Index Dosing Guide
Overview
The Estimative Index (EI) coined by Tom Barr is a straight forward method for providing nutrients for a planted tank. The idea behind EI is simply introducing an excess amount of nutrients within an aquarium, throughout the week. This excess of nutrients floods the water column and feeds the plants. This is an estimative method; measuring specific nutrient uptake rates is not necessary and no test kits are involved. EI provides a surplus of nutrients that helps to prevents plant deficiencies, and allows plant growth to out compete algae growth.
The process of which this is done is simple. Each day fertilizers are dosed, and the nutrients are absorbed by the plants. With this method being estimative, we can dose fertilizers according to general guidelines suited for our particular setup (see below). At the end of the week, one performs a 50% water change to ‘reset’ the nutrient load in the entire system. And then the entire dosing schedule is repeated.
The primary fertilizers are the macro nutrients - Nitrogen (N), Phosphorous (P), Potassium (K), and the micro nutrients – trace elements (Plantex CSM+B, Flourish). Iron (Fe) can also be supplemented if necessary.
The Estimative Index method works best for a high light and well planted aquarium. However it is not limited to lower light setups, smaller quantities of fertilizers should be dosed in those instances.
General Dosing Guideline for High Light and Well Planted Aquariums
10- 20 Gallon Aquariums
+/- 1/8 tsp KN03 (N) 3x a week
+/- 1/32 tsp KH2P04 (P) 3x a week
+/- 1/32 tsp (2ml) Trace Elements 3x a week
50% weekly water change
20-40 Gallon Aquariums
+/- ¼ tsp KN03 3x a week
+/- 1/16 tsp KH2P04 3x a week
+/- 1/16 tsp (5ml) Trace Elements 3x a week
50% weekly water change
40-60 Gallon Aquariums
+/- 1/2 tsp KN03 3x a week
+/- 1/8 tsp KH2P04 3x a week
+/- 1/8 (10ml) Trace Elements 3x a week
50% weekly water change
60 – 80 Gallon Aquariums
+/- 3/4 tsp KN03 3x a week
+/- ¼ tsp KH2P04 3x a week
+/- ¼ tsp (20ml) Trace Elements 3x a week
50% weekly water change
100 - 125 Gallon Aquarium
+/- 1 1/2 tsp KN03 3x a week
+/- ½ tsp KH2P04 3x a week
+/- ½ tsp (30ml) Trace Elements 3x a week
50% weekly water change
Example Dosing Regime for 29 Gallon:
Note: K2SO4 is not required for dosing unless you need the extra Potassium (K). This K is found in KN03 and KH2P04. Dosing these two according to above will yield sufficient K levels. Therefore, one will be fine dosing only KN03 and KH2P04, and Plantex. If one needs to increase their K levels with K2S04, add the same measured amount as KH2P04. For example, if one is dosing 1/2 tsp of KH2P04, then dose 1/2 tsp of K2S04. In true regards to EI, added excess K is not detrimental in any event.
EI target ranges
CO2 range 25-30 ppm
NO3 range 5-30 ppm
K+ range 10-30 ppm
PO4 range 1.0-2.0 ppm
Fe 0.2-0.5ppm or higher
GH range 3-5 degrees ~ 50ppm or higher
KH range 3-5
And...Finally you would need to Add Macro Fertilisers as below
MACRO
N, P, K
Nitrogen, Phosphorous and Potassium - the macro nutrients.
* 500 ml of distilled water
* 61 g (10.69 teaspoons, 3.63 tablespoons) Potassium nitrate (KNO3)
* 5.2 g (1 teaspoons) Potassium monophosphate (KP04)
* 10.8 g (2 teaspoons) Magnesium sulphate (MgSO4)
* 1.8 g (0.3 or 1/3 teaspoon) Potassium sulphate (KSO4)
3 times a week add 10 ml for a 20 gallon tank. Or 1-2 ml daily. Or 15 ml twice a week. This will add 30 ppm nitrate a week to a tank with corresponding correct proportions for the other macro nutrients.
& FE + Trace Elements as below
FE + Trace
Iron and trace elements.
* Use 71 grams (2.5 T) of Plantex CSM+B
* one liter of distilled water.
Use 1 cc per 2 gal to raise Fe 5.0 ppm. i:e 20 gal tank gets 10cc (two capfuls)
Dose daily, biweekly or weekly depending on bio load
The Estimative Index (EI) coined by Tom Barr is a straight forward method for providing nutrients for a planted tank. The idea behind EI is simply introducing an excess amount of nutrients within an aquarium, throughout the week. This excess of nutrients floods the water column and feeds the plants. This is an estimative method; measuring specific nutrient uptake rates is not necessary and no test kits are involved. EI provides a surplus of nutrients that helps to prevents plant deficiencies, and allows plant growth to out compete algae growth.
The process of which this is done is simple. Each day fertilizers are dosed, and the nutrients are absorbed by the plants. With this method being estimative, we can dose fertilizers according to general guidelines suited for our particular setup (see below). At the end of the week, one performs a 50% water change to ‘reset’ the nutrient load in the entire system. And then the entire dosing schedule is repeated.
The primary fertilizers are the macro nutrients - Nitrogen (N), Phosphorous (P), Potassium (K), and the micro nutrients – trace elements (Plantex CSM+B, Flourish). Iron (Fe) can also be supplemented if necessary.
The Estimative Index method works best for a high light and well planted aquarium. However it is not limited to lower light setups, smaller quantities of fertilizers should be dosed in those instances.
General Dosing Guideline for High Light and Well Planted Aquariums
10- 20 Gallon Aquariums
+/- 1/8 tsp KN03 (N) 3x a week
+/- 1/32 tsp KH2P04 (P) 3x a week
+/- 1/32 tsp (2ml) Trace Elements 3x a week
50% weekly water change
20-40 Gallon Aquariums
+/- ¼ tsp KN03 3x a week
+/- 1/16 tsp KH2P04 3x a week
+/- 1/16 tsp (5ml) Trace Elements 3x a week
50% weekly water change
40-60 Gallon Aquariums
+/- 1/2 tsp KN03 3x a week
+/- 1/8 tsp KH2P04 3x a week
+/- 1/8 (10ml) Trace Elements 3x a week
50% weekly water change
60 – 80 Gallon Aquariums
+/- 3/4 tsp KN03 3x a week
+/- ¼ tsp KH2P04 3x a week
+/- ¼ tsp (20ml) Trace Elements 3x a week
50% weekly water change
100 - 125 Gallon Aquarium
+/- 1 1/2 tsp KN03 3x a week
+/- ½ tsp KH2P04 3x a week
+/- ½ tsp (30ml) Trace Elements 3x a week
50% weekly water change
Example Dosing Regime for 29 Gallon:
Note: K2SO4 is not required for dosing unless you need the extra Potassium (K). This K is found in KN03 and KH2P04. Dosing these two according to above will yield sufficient K levels. Therefore, one will be fine dosing only KN03 and KH2P04, and Plantex. If one needs to increase their K levels with K2S04, add the same measured amount as KH2P04. For example, if one is dosing 1/2 tsp of KH2P04, then dose 1/2 tsp of K2S04. In true regards to EI, added excess K is not detrimental in any event.
EI target ranges
CO2 range 25-30 ppm
NO3 range 5-30 ppm
K+ range 10-30 ppm
PO4 range 1.0-2.0 ppm
Fe 0.2-0.5ppm or higher
GH range 3-5 degrees ~ 50ppm or higher
KH range 3-5
And...Finally you would need to Add Macro Fertilisers as below
MACRO
N, P, K
Nitrogen, Phosphorous and Potassium - the macro nutrients.
* 500 ml of distilled water
* 61 g (10.69 teaspoons, 3.63 tablespoons) Potassium nitrate (KNO3)
* 5.2 g (1 teaspoons) Potassium monophosphate (KP04)
* 10.8 g (2 teaspoons) Magnesium sulphate (MgSO4)
* 1.8 g (0.3 or 1/3 teaspoon) Potassium sulphate (KSO4)
3 times a week add 10 ml for a 20 gallon tank. Or 1-2 ml daily. Or 15 ml twice a week. This will add 30 ppm nitrate a week to a tank with corresponding correct proportions for the other macro nutrients.
& FE + Trace Elements as below
FE + Trace
Iron and trace elements.
* Use 71 grams (2.5 T) of Plantex CSM+B
* one liter of distilled water.
Use 1 cc per 2 gal to raise Fe 5.0 ppm. i:e 20 gal tank gets 10cc (two capfuls)
Dose daily, biweekly or weekly depending on bio load
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