Aquatic Plant Forum banner
Cancel

Estimative Index Dosing Guide

469588 Views 224 Replies 99 Participants Last post by  mistergreen, 
J
Overview
The Estimative Index (EI) coined by Tom Barr is a straightforward 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
(wolfenxxx)

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

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

Where to buy fertilizers?
AquariumFertilizers. com could have provide you with the necessary chemicals for dry and liquid dosing of the above but is out of buisness. For micro - trace elements, Plantex CSM+B, Seachem Flourish, and Tropica AquaCare are equivalent to each other. Drsfostersmith and bigalsonline for the Seachem and Tropica brands.

One Pound of each of Aquarium Fertilizer/Greg Watson's Chemicals will last at least 1 year:
Plantex CSM+B​
Potassium Nitrate KN03​
Monopotassium Phosphate KH2P04​
Potassium Sulphate K2S04 (optional)​

Special Notes:

Providing optimal CO2 levels of at least 30 ppm are necessary for plants to prosper and out-compete algae. If algae issue arise, remove all visible algae and infected leaves. Recheck CO2 levels, and possibly reduce and adjust the lighting period.

Direct dry dosing into the tank is perfectly fine. Many dosing straight into the tank, or they dissolve each chemical in water before adding.

Making a Liquid Stock of Plantex CSM+B is more often mixed into a bulk liquid solution since some find it more convenient to dose their trace elements this way. The recipe for this solution is 1 tablespoon to 250ml water is equivalent to: 20 ml = 1/4 teaspoon of dry Plantex. This solution is stored in refrigerators to prevent mold from forming within the container.

Small dosing teaspoons (smidgen, dash, pinch) can be found at Linen & Things, Bed Bath and Beyond, Wal-Mart, dollar stores, eBay and other online retailers. To identify the specific measurements of your smidgen, dash, pinch set, a 1/8 tsp should fill a ¼ tsp in 2 tries, 1/16 tsp in 4 tries, and a 1/32 tsp in 8 tries.

Stick to a good dosing regime and your plants will flourish!
See less See more
Reply
Save
Like
  • Like
Reactions: 3
21 - 40 of 225 Posts
Laith
What you should not do is mix KH2PO4 and any Fe trace mix in a bottle in order to dose them together. The concentrations in the bottle will be such that the Fe and PO4 will combine (FePO4) and precipitate out.

However, adding each separately to a tank shouldn't be a problem as they will very quickly become very diluted. Using autodosing I dose both every day but just to be on the safe side they are dosed a couple of hours apart. I probably wouldn't have any problem dosing them within minutes of each other or even at the same time at different spots in the tank...
Reply
Save
Like
Squawkbert
2 notes
- CaCO3 has limited solubility so you may want to pre mix it in a little hot water, then add it in w/ replacement water during a pwc.

K2HPO3 (dibasic potassium phosphate) is more readily soluble than the monobasic variety and it adds twice the K per unit. Drawbacks - may not be as readily available to everyone, pH is higher than for the monobasic. There is a "tribasic" out there, but it's even less common in labs etc., pH would be higher still and it's no more soluble than dibasic (if memory serves).
Reply
Save
Like
eklikewhoa
Thanks for clearing that up.
Reply
Save
Like
N
Well let me see if i understand everything :)

I'm used to liquid solution, litters and grams so i will use this units ;) and i will use Chuck's online calculator

I'm going to try EI in a 30 litter water tank (7.93 gallons) so will pick the 10-20 gallon example (off course i will reduce a little the fertilization, but thats a detail for now)

10- 20 Gallon Aquariums

+/- 1/8 tsp = 0.125 g of KN03 (N) 3x a week
+/- 1/32 tsp = 0.15 g KH2P04 (P) 3x a week
+/- 1/32 tsp (2ml) Trace Elements 3x a week
50% weekly water change

As i say i will make a 250 ml of KNO3 and 250 ml of KH2PO4 and i will fertilize 5ml 3x a week. So by my math:

KNO3
6.2 g for 250 ml = 0.51 ppm => 0.51 ppm * 5 = 2.55 ppm = 1/8 tsp of KNO3

KH2PO4
7.5 g for 250 ml = 0.7 ppm => 0.7 ppm * 5 = 3.5 ppm = 1/32 tsp of KH2PO4

Please let me know if this math is correct!

This is a simple example of what to do to convert dry ferts in solutions ferts :cool:
See less See more
Reply
Save
Like
J
The goal is to have at least 5 ppms of Nitrate per dosage. So by increasing the KNO3 mixed in the 250 ml solution, we can get 1 ppm per 1 ml dosed.

KNO3
12 g for 250 ml. 5 ml of stock solution dosed is 5 ppm of N, thereby hitting the target goal.

KH2PO4
Calculations above look good. However, instead of using the full 5ml dosage, only 2-3 ml 3x a week is needed.

-John N.
Reply
Save
Like
N
Tanks very much, i will try it :cool:
Reply
Save
Like
O
Ok guys... I have a 160 gallon aquarium that is planted and I want to try EI dosing. I am completely new to the EI dosing scene and want to know what I should buy from Greg Watson's, and what would be a good dose amount and how often?

THx
Reply
Save
Like
hoppycalif
Assuming you have average tap water, you need KNO3 and KH2PO4. You also need a source of trace elements, which can be Greg Watson's CSM+B or it can be a commercial trace mix, such as Flourish. Your big tank will go through commercial trace mixes pretty fast, so CSM+B would be the best idea. Assuming you have about 300 watts of PC quality light with good reflectors, I would start by dosing 2 tsp KNO3 3X per week, 3/4 tsp KH2PO4 3X per week, and 1/2 - 3/4 tsp CSM+B (dosed dry) 3X per week. If you have much lower light than 300 watts, I would cut down to 2X or less per week. If your water has a low GH, or little or no Mg component of the GH I would dose Greg Watsons Barr GH builder too.
Reply
Save
Like
Laith
ocdiscus said:
Ok guys... I have a 160 gallon aquarium that is planted and I want to try EI dosing. I am completely new to the EI dosing scene and want to know what I should buy from Greg Watson's, and what would be a good dose amount and how often?

THx
Click to expand...
http://www.aquaticplantcentral.com/...zing/15225-estimative-index-dosing-guide.html
Reply
Save
Like
  • Like
Reactions: 1
Laith
:rolleyes: Sorry, I just realized I referenced this same thread... Not enough coffee that morning... :p

For a 160g you could start out with the dosing suggested for a 100-135 gallon tank. Watch the plants and adjust accordingly. Assuming 140g of water in your tank, that dosing will give you almost 10mg/l of NO3 per dose and just over 3mg/l of PO4 per dose. You could even start out with slightly lower PO4 dosing.
Reply
Save
Like
projectile
best overview i have seen of EI , thanks a lot
Reply
Save
Like
ezeke1
Good stuff, thanks for the guide!
Reply
Save
Like
S
John N. said:
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
Click to expand...
These ranges, are they weekly totals?

Using the suggestions higher up in the post, in a 50 gal I get
25.27ppm NO3 a week
7.74ppm PO4 a week and
19.11ppm K a week assuming zero plant uptake.

So that puts NO3 & K in the right range, but PO4 nearly 6ppm too high. I realize that Toms point is excesses are ok if there is nothing lacking but this seem excessive when reduced KH2PO4 can be dosed and adding K2SO4 to make up for the loss in K.

I am I reading it right that there is too much PO4 according to the listed target ranges?
Reply
Save
Like
J
As you noted, the ppms per week represent the chemical accumulation without any plant uptake or consumption. Of course zero uptake is not what happens in our aquariums. The wide ranges listed above describe the daily totals with uptake that can happen through the course of a weekly dosage. What does that mean?

Plants consume a good amount of the nutrients in high light situations each day, however they can't eat all of it! From day one, the nutrient load climbs into the upper excess tiers by the end of the week. The 50% weekly water change flushes the system so that the levels are then reduced.

The more debated day to day range can be denoted as:

CO2 range 25-30 ppm
NO3 range 5-15 ppm
K+ range 10-15 ppm
PO4 range 1.0-2.0 ppm

-John N.
Reply
Save
Like
S
Thanks for your reply. I understand what you are saying, but can't understand why all the levels are within the suggested targets except the PO4. As these are assuming zero uptake, is it assumed that the plants will consume PO4 faster than the other levels and so these excessive levels won't be seen?
Reply
Save
Like
J
PO4 is dosed in low quantities and also consumed in low quantities, whereas the other chemicals have a wider range and wider range of consumption values. It can be stated that 3ppm of PO4 dosed between day 1 and the next dose on day 3 will be consumed to its depletion. I'm not sure if that makes sense to you, but I'm sure there will be a better explanation than mine coming along.

-John N.
Reply
Save
Like
M
Thanks for the abundant amount of information. Now to digest it all and figure out what I need to do for my tank.
Reply
Save
Like
L
If dosing flourish comp instead of CSM+B how much would i add for a 20-40 gallon tank? Also would i want to add flourish iron on which day? i have a 37 gallon tank
Reply
Save
Like
J
For both Seachem Flourish and Iron, dose according to the directions on the bottle. Dose both on the micro element dosing days, and do the 50% waterchange at the end of the week as normal.

-John N.
Reply
Save
Like
L
ok i will give it a try thanks for the clarification
Reply
Save
Like
21 - 40 of 225 Posts
This is an older thread, you may not receive a response, and could be reviving an old thread. Please consider creating a new thread.
Aquatic Plant Forum
A forum community dedicated to aquatic plant owners and enthusiasts. Come join the discussion about collections, displays, tanks, styles, troubleshooting, reviews, accessories, classifieds, and more!
Full Forum Listing
Explore Our Forums
General Aquarium Plants Discussions For Sale or Trade El Natural DIY Aquarium Projects Equipment
Top