Lifetime Charter Member
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Jan 5, 2009
Washington, DC
:p When plants find sufficient nutrients,
energy is available for photosynthesis,
Carotenoids, Xanthophylls and Chlorophyll - oh my. :cool:

Mid-Light (45-80mmol PAR) - High Tech :rolleyes: (CO2)
50% Weekly Water change.

T20 gal:
24" x 12" x 16"

NPK - Dose/weekly,

5 ppm N-NO3
DC tap water contains ruffly 2ppm NO3 & PO4, respectively.

Trace - Dose, as needed.
Fe is a proxy for trace nutrients in Plantex.
0.2ppm Fe & 0.02 dGH

Typical uptake rates with non-limiting CO2, per day (24 hours):

N-No3 x 4.43 =

Admin;217 said:
  • NO3 1-4ppm
  • NH4 0.1-0.6ppm (do not dose NH4!It will cause algae)
  • PO4 0.2-0.6ppm
These rates do not assume that you will show deficiencies if you dose less than this, but adding more than these rates will not help further plant health. This is a point that the aquarist needs to understand.

Basically, it is extremely unlikely your plants will ever need more than these rates even at high light intensities. Adding enough nutrients to prevent anything from becoming deficient is the goal, not precise uptake and growth requirements.
Tom Barr;n184404 said:
NH4 loading from more and more fish seems to cause algae...
Plants will not need/use more than 0.8 pp m to maybe 1 ppm per day under 99.99% of cases.

E.I. Stock Solutions
- Dose 1 mL, every 20 Liters.

1,000 mL
  • 234 g. KNO3 ~ 15 Tbsp
  • 10cc Excel
Ambit 0.8
1,000 mL
  • 20 g. KH2PO4 ~ 1.3 Tbsp
  • 58 g. K2SO4 + ~ 3 Tbsp
  • 10cc Excel
411 Flexx *.
900 mL
  • 55g Plantex CSM+Boron ~ 4 Tbsp
4:1:1 Option
  • DTPA ~ 3 tsp
  • Fe gluconate ~ 3 tsp
CSM+B Trace
Fe 7% Mg 1.50% Cu 0.1% B 1.18%
Mn 2% Zn 0.4% Mo 0.06%

CSM+B DIY Formula ~ Biollante
Comparison Of Trace Products ~ James' Planted Tank

How to prevent mold/bacteria & stock recipes :
  1. Take distilled water and anti-fungal solutions.
  2. Wait five - ten minutes.
  3. Add fertilizer & Top off to 1 liter.
*Chelated Fe types.
Tom Barr;46541 said:
For moderately hard water consider using DTPA Fe in addition to Plantex.
Tom Barr;46154 said:
CMS+B, Fe Gluconate and DTPA Fe at 4:1:1 ratio by volume.
Tom Barr;n218546 said:
Haller et al suggested 6-8 ppm of Fe as ETDA for optimal Hydrilla growth.
I add DTPA to CMS+B as well as Fe Gluconate. But my tap is low KH, at higher KH, you can see the Fe cloud. DTPA is more appropriate in such cases(so add 2 DTPA and 3 CMS+B in that case). Normally I use Fe Gluc 1; 1 DTPA; 3 CMS: or 1:1:3
Practical PMDD Information (Sources & Doses)

Tom Barr;41428 said:
Plantex CSM+B is often mixed into solution for liquid dosing. 1 tablespoon to 250ml water is equivalent to: 20 ml = 1/4 teaspoon of dry Plantex.
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Lifetime Charter Member
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Jan 15, 2009
You can keep the DIY yeast clean in a couple of ways. One is to install a DIY bubble counter. Essentially you get a second bottle. Fill it with some water maybe half way or so. In the cap drill two holes. One will go to the tank and the other to the yeast bottle. The yeast bottle tube will run into the bubble counter through the cap and needs to have the hose ( or a connected tube ) down near the bottom of the bottle or under the water level. The tube to the tank needs to be well above the water line. CO2 will bubble up through the water. Any yeast which escapes will be trapped by the water and only the CO2 will bubble up out the top and on into the tank. When replacing the yeast solution you can just replace the water in your bubble counter at the same time if it's dirty.

The other way would be to lower the water level in the yeast bottle. I've done reasonably well with your standard 2 Liter Coke bottle. Throw a couple cups of sugar and yeast into the bottle and make sure it is filled no higher than the top of the label. As long as the tube doesn't hang too far into the bottle you should have sufficient clearance that the yeast bubbling away doesn't make it high enough to enter the tube. This is probably the simplest of the two methods but won't do anything to stop yeast if it gets high enough. The other method will filter it out.



Lifetime Charter Member
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Jan 5, 2009
Washington, DC
Arbitrary Recollections of Plant Nutrition and Causal Effect.

Nutrient reactions
in accordance with Liebig's law of minimum.
"When two or more factors limit growth, addition of just one will have little effect. The provision of both will have a much greater influence"
Marginally low in a number of nutrients, one unavailable nutrient limits overall growth, over time.
Increase supply of that limiting nutrient, even slightly, increasing the demand for nutrients and another nutrient, the next unavailable, becomes limiting.
Macro Nutrients

C, H, O, N, P, K, S, Ca and Mg
Mobile and Non-mobile elements.
Mobile nutrients -
can be reclaimed from old leaves and used to produce new growth.
Non-mobile nutrients can not and nutrient deficiencies show up in new growth.

Plant Deficiency Checklist + Diagram
Plant Diseases & Nutrient Disorders

Carbon (Non-mobile)
CO2 and Light
35-40 mg/L
Non CO2 methods
Dissolved organic carbon (DOC).

Carbon - Tom Barr

After ten days of CO2 supplementation there should be a noticeable increase in growth.

Environments with elevated CO2 will require non-limiting macro-nutrient and trace due to the vigorous nutrient uptake from the plants. Moderately lit aquatic environments with ample CO2 have 4 ~ 5 times greater growth then low or inconstant CO2 levels. Under higher lighting, CO2 is essential or plants quickly becomes CO2 limited, leading to growth deficiencies and unwanted algae.

Hydrogen is necessary for building sugars and building the plant. It is obtained almost entirely from water. Hydrogen ions are imperative for a proton gradient to help drive the electron transport chain in photosynthesis and for respiration.

Barr Report Newsletter (BRN) - Oxygen
✒ Dissolved Oxygen
The efficiency of nitrifying bacteria is at it's best when the water is near oxygen saturation and most oxygen concentrations below 5 ppm are not considered healthy. The approximate saturation level for oxygen at 50° F. is 11.5 mg/l; at 70° F., 9 mg/l; and at 90° F., 7.5 mg/l. Impurities added to the water (i.e. salt) or an increase in altitude (above sea level) further decrease these saturation levels.

Energy from respiration drives metabolic processes. In plants these processes include the absorption of plant nutrients (salts) into roots, transport of potassium (K) into and out of guard cells. Other functions: synthesis of proteins, lipids and structural components of plants such as cellulose and other fibers all require O2. Synthesis of storage compounds in stems, roots and seeds also require O2.

Nitrogen (very mobile)
BRN - Nitrogen
Nitrogen cycle.
N-NO3 (Paul Krombholz)

DC Tap, 0.5 - 3 ppm N-NO3,
Fish waist, (ammonia / nitric acid).
N-NO3 ≮ 24 ppm

The leaves of a nitrogen deficient plant show an over-all yellow or light green color. The older leaves are more affected than the newer growth because nitrogen is mobile within the plant and will move from the older foliage to newer leaves when in short supply. Older leaves are reabsorbed starting at the tips if the leaf. Plants w/severe nitrogen deficiency can become white/yellow w/tinny leaves.
3 Day exposure to 120ppm of NO3-NO3 (derived solely from KNO3) and 50% mortality rate with C. japonica (Amano algae eating shrimp).
The same has no effect on health of 20 South American species of fish (Barr, 2005).
Calcium (Non-mobile)
Ca++ ≮ 10ppm
DC Tap water 44ppm
BRN - Calcium
Thought to enhance uptake of N-NO3. Calcium deficiency can cause stunting of the terminal buds; developing roots, distorted new growth (twisted, bent, maybe cupped leaves) black spots/white leaf margins and impaired root function.
Magnesium (mobile)
Mg++ ≮ 3
DC Tap water ~9ppm
BRN - Magnesium
Magnesium is the only mineral constituent of the chlorophyll molecule accounting for near 20% of total Mg in plants. Magnesium serves as a structural component necessary for protein synthesis. Most reactions involving phosphate transfer specific to ATP require this element, as well as, the activities of several other enzymes. As an example, insufficient magnesium can restrict RuDP carboxylase and CO2 assimilation. Deficiency symptoms often result in leaf distortion for this reason. Other symptoms include interveinal chlorosis of the lower leaf, in which the veins remain green; advancing to uniform pale yellowing of the leaf, to brown and necrotic. There are no tests of Mg that I know of. To test for Mg, test for PPM General hardness as CaCO3 and test for PPM Ca hardness as CaCO3, i.e., PPM General hardness as CaCO3 minus PPM Ca hardness as CaCO3 = PPM Mg hardness as CaCO3.​
My tap water's total hardness (GPG), 5.3 - 11
Alkalinity is 37 - 111ppm​

Phosphate (mobile)
DC Tap, ~0.02 ppm, P-PO4.
Fish waist/Fish food
  • A useful animal cell buffering agent, a component of DNA, RNA, ATP, phospholipids, bulbs and flowers.
  • GSA, indicates high levels of light, low phosphate and/or low CO2.
  • Phosphorus deficiency symptoms are not very distinct and thus difficult to identify. Unlike nitrogen deficiency, young to mature leaves remain dark green at all levels of severity. In most (but not all) cultivars, yellowing is preceded by the appearance of purple anthocyanin pigments, producing a range of autumnal colors in the senescing leaves. Yellowing may spread from discrete interveinal patches, often affecting one half of the blade more than the other - yellowing and necrosis is often asymmetrical. Potassium and magnesium deficiencies also cause chlorosis on older leaves, but in phosphorus deficiency chlorosis usually does not retain a distinct interveinal pattern, as is typical of potassium or magnesium deficiencies. A major visual symptom is that the plants are dwarfed or stunted.
Potassium (very mobile)
Deficient in potassium, plants will be deficient in phosphate and/or nitrate uptake reactions.
Plants w/severe potassium deficiency have pin-holes in the leaf that enlarge with a yellow edge surrounding the holes. The leaf is otherwise normal looking. BRN - Potassium
Sulfate (Moderately mobile)
DC Tap water ~54ppm
BRN - Sulfur

Although sulfur is most often regarded as a secondary nutrient,
plant requirements for sulfur are equal to and sometimes exceed those for phosphorus.

However, due to the levels in tap water and added fertilizer, it is rarely limited.
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Mar 12, 2009
Get your self some KH2PO4, much easier to work with than figuring out seachem's product. You can reduce your constant measuring with everything if you just make a bottle of macros in DI and dose by ml. I find it offers more accuracy and less work; a tsp measure has a far larger margin of error than a middling scale.



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Jan 5, 2009
Washington, DC
Micro Nutrients
Fe, Mn, Zn, Cu, B, Ni, Cl and Mo​

Tom Barr;4188 said:
Ratios of and in themselves have much less impact and significance....

Iron (Nonmobile)
DC Tap water ~0.02ppm
Iron deficiency results in interveinal chlorosis of the younger foliage (yellow foliage, green veins).
If the condition worsens the newly formed leaves may remain small and can become completely pale yellow to white.
Fe transfers energy from PS's to the dark reactions, ferroredoxins. Unless it is a severe case the symptoms of iron deficiency can recover.

Fe uptake and active Fe in plants
BAR - Iron and Manganese.
Manganese (Nonmobile)
Do you want more? Wet's "Good Shit".
DC Tap water ~0.0012ppm​

Zink (mobile)
DC Tap water ~0.0021ppm
Copper (Nonmobile)
✒ BAR - Copper and Zinc
DC Tap water ~0.008-0.1ppm
CSM+B ~0.005ppm
The LC50 for CuSO4 is around 0.46ppm for cherry shrimp.​

Molybdenum (mobile)
Mo ≯ 0.01ppm
DC Tap water 0.001ppm
BAR - Boron and Molybdenum
Most molybdenum in plants is concentrated in the enzyme nitrate reductase, essential to inorganic nitrogen assimilation (Reduces NO3 to NO2 and then quickly to NH4 for assimilation into amino acid production) occurring in the envelope of chloroplasts in leaves. As such, deficiency symptoms are very similar to those for nitrogen and potassium deficiency. Molybdenum may also play a part in iron absorption and translocation in plants and increase antioxidant function. Molybdenum deficiencies are rare, in most cases. However, excessive dietary intake of molybdenum results in copper deficiency in some animals.

DC à la carte:
pH 7.6 with an Alkalinity of 62ppm as CaCO3
Cl ~32ppm ❦ Na ~16ppm ❦ Ni ~0.002ppm ❦ Al ~0.049ppm ❦ Iodide ~0.027ppm ❦ B (ND) ❦ Co (ND)​

To improve overall nutrient availability both an enriched soil and water column dosing are often recommend. There are many benefits from employing them both. The following links provide discussions and information on several soil amendments used in the hobby.
Further Reading on water column dosing:
EI Dosing, or No Need for Test Kits
Deficiencies - James' Planted Tank
Mineral Deficiency - Lincoln Taiz and Eduardo Zeiger
List of Recommended Levels and Parameters - Tom Barr
Parameters,1996-1997 - Tom Barr
Calibrating Test Kits - for Non-Chemists - Hoppy
Enzymes - Tom Barr
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Tom Barr

Staff member
Jan 23, 2005
I'd not worry much about anything related to K+ and traces.
Spend your time with light, CO2 etc.

Tom Barr


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Jan 5, 2009
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CO2 is all that is left, but a critical dosing parameter, more so than any other.
Sicne it is central to plant growth, any limitation of a fert will influence it's uptake and phenotypic growth expression radically. - Tom Barr
Carbon pathway, why CO2 stability is so important?
Tom Barr;39979 said:
Many dosing methods suggest that they have some way of solving all your algae issues. Curiously, such methods also fail to address algae growth and causes at the root.

Plants have a rough time adapting to different CO2 levels, algae do not(they are virtually never limited by CO2). Plants need to make a lot more Rubsico to adjust to lower levels, often several times more(10-20X with CO2 enriched vs no CO2) and it takes time for the plant to make these enzymes.

Changing CO2 around day to day, hour to hour, week to week the plant struggles and spends more energy adapting to CO2, than with growth, acquiring nutrients, catching light etc. In non CO2 systems, changing water frequently causes a spike in high CO2 week to week etc, done only once every few months is better.

For CO2 enriched tanks(non limiting CO2 systems), changing water has no such impact. The plants do not need to adapt to CO2 since they have ample CO2 and supply for all conditions.

Add CO2 and the plant's demand for nutrients becomes more vigorous.

Tom Barr;41151 said:
Put another way; when the plants needs are met and grow well, algae does not.

"At low light and low CO2 there is not much energy to play around with for up or down-regulation of the pools of Chlorophyll or enzymes. If we then add a little more CO2 to the system the plant can afford to invest less energy and resources in CO2 uptake and that leaves more energy for optimizing the light - more Chlorophyll can be produced without fatal consequences from the energy budget. Hence, we have not raised the light and the plants can now utilize any available light - more efficiently." - Tropica

Tropica's study on Riccia and the affect of resource availability on growth. :cool:

Diagram courtesy of John LeVasseur

How much CO2?
A 0.7 drop in pH due to CO2 means the ppm of CO2 in the water went up by a factor of 10 to the .7 power, or about a factor of 5.
Assuming the water had 3 ppm before the CO2 was added, you would have about 15 ppm of CO2 - irregardless of the KH.

The pH drop is relative to ambient CO2 levels of about 2-3ppm, irregardless of KH.
From there a pH drop of 1.0- to 1.3 would correspond to a CO2 level around 30-45 ppm on the chart.

Liquid Carbon
Excel/Glutaralehyde is often dosed as a carbon source for plants.
The typical full dose adds roughly 2.1 ppm of Glut per dose(5mls in 10 Gal).

Toxicity starts at about 4-5ppm for invertebrates.
Drop off is rapid, 1/2 life is likely 12 hours or less, 24 hours it is completely gone.

Standard uptake vs growth for light, CO2 and nutrients - Marcel/kwisatz


The Drop Checker
One drop checker is good...
Measuring CO2 Levels
Estimating CO2 levels regardless of KH
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Jan 5, 2009
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How much Light?

30-50micromol along the sediment is ample light for ANY species.


Diagram courtesy of VaughnH/Hoppy

PAR vs Distance, T5, T12, PC


Diagram courtesy of VaughnH/Hoppy

Diagram courtesy of VaughnH/Hoppy

Lighting an Aquarium with PAR instead of Watts, Hoppy


The high light requirement myth

CO2 and Light Stimulate Growth, - Tropica

All You Ever Wanted To Know About CO2 But Were Afraid To Ask

Lighting an Aquarium with PAR instead of Watts

LED Lighting Compendium

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