# [Wet Thumb Forum]-Lets talk about iron and micros. Experts only.



## m.lemay (Jan 9, 2005)

I want to start a discussion about iron and micro dosing. The goal here is to get some real data about what works and what doesn't. It's my hope that we can come up with some real hard solutions to this perplexing little "mystery".

I know I'm not the only one that feels like theres no real substance to micro dosing. 

Macros for the most part have been real simple. 10ppm nitrates, 1ppm phosphate, 10-30ppm potassium, simple right. Maintain a 10-1 ratio of nitrate to phosphate and alls well. Plus there's lots of room to experiment with fairly quick consequences when deviating from these parameters, which makes it fairly easy to determine cause and effect. Not so with micros. It can take weeks for plants to respond to micros.

Here's some thoughts or questions we might want to discuss:

Are iron tests really useless?
What about the Lamotte/Hach iron tests.
Do we need more iron than Plantex CSM+B offers? If so how much more?
Anyone using Iron Chelate 10% from GregWatson.com? If so, Whats your experience?
Whats your experience for dosing maximum color?
How much is too much micros?
Any other thoughts that would be relevant are also welcome.

I'd like to confine this discussion to planted tank enthusiasts who have something to offer in the way of real experience in this area. 

Please don't post general questions about micro dosing in this thread.

Let the discussion begin.
Marcel


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## m.lemay (Jan 9, 2005)

I want to start a discussion about iron and micro dosing. The goal here is to get some real data about what works and what doesn't. It's my hope that we can come up with some real hard solutions to this perplexing little "mystery".

I know I'm not the only one that feels like theres no real substance to micro dosing. 

Macros for the most part have been real simple. 10ppm nitrates, 1ppm phosphate, 10-30ppm potassium, simple right. Maintain a 10-1 ratio of nitrate to phosphate and alls well. Plus there's lots of room to experiment with fairly quick consequences when deviating from these parameters, which makes it fairly easy to determine cause and effect. Not so with micros. It can take weeks for plants to respond to micros.

Here's some thoughts or questions we might want to discuss:

Are iron tests really useless?
What about the Lamotte/Hach iron tests.
Do we need more iron than Plantex CSM+B offers? If so how much more?
Anyone using Iron Chelate 10% from GregWatson.com? If so, Whats your experience?
Whats your experience for dosing maximum color?
How much is too much micros?
Any other thoughts that would be relevant are also welcome.

I'd like to confine this discussion to planted tank enthusiasts who have something to offer in the way of real experience in this area. 

Please don't post general questions about micro dosing in this thread.

Let the discussion begin.
Marcel


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## TWood (Dec 9, 2004)

I'm no expert (few here are) but...



> quote:
> 
> It can take weeks for plants to respond to micros.


I use the color of new growth on h. difformis as an indicator for low iron (Fe) - Pale growth means Fe is too low. The plants respond within HOURS after adding CSM+B to get Fe at 0.1ppm.



> quote:
> 
> Do we need more iron than Plantex CSM+B offers?


That question makes no sense and reveals an underlying confusion. CSM+B has a known amount of Fe in it. If you want more Fe in the tank, then add more CSM+B to the tank. Use the Fertilator to dose as much as you want to get to a target level:

http://www.aquaticplantcentral.com/forum/fertilator.php

Don't bother making a solution, just add the dry powder until the calculator says you've added enough. I usually dose to get 0.1 ppm Fe.

Remember too, the dosing for Fe, when part of a micromix, is also used as a proxy to get the other micronutrients correctly dosed. The idea is, that if you dose Fe to a certain level, then all the other micros will fall into line in the proportion that they exist in the micronutrient mix. Just dosing Fe alone doesn't accomplish that broader goal.

TW


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## m.lemay (Jan 9, 2005)

You're assuming that Plantex is the perfect mix for all plants all the time. 

The question makes a lot of sence in that ,what if as your dosing plantex your overdosing unnecesary and potentially dangerous elements such as copper (present in Plantex)in order to obtain the optimum iron level. All the other stuff you stated is all true but far too simple for this discussion.


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## Roger Miller (Jun 19, 2004)

Most if not all of the mico nutrients have been determined to be harmful to aquatic life at rather low levels. That does not mean that any of them would be toxic to whatever you keep in your aquarium. Nor does it mean that you would necessarily observe the damage even if it were present. Some levels according to the EPA goldbook are:

Iron 1 milligram/liter dissolved, any form.
Boron 750 micrograms/liter
Nickle 119 micrograms/liter at 4 dGH (long term)
Zinc 80 micrograms/liter at 4 dGH (long term)
Copper 9 micrograms/liter at 4 dGH (long term)

The "safe" level of nickle, zinc and copper increases with hardness; also levels for short term exposures are higher than levels for long term exposures. The standard for iron is for any dissolved form including chelated and complexed forms. The standard for boron is actually established for irrigation water and may consider effects from evaporative concentration in soils.

Using tested iron levels as an indicator for other trace nutrients is an established practice. The chemistry of iron is different from the chemistry of other trace nutrients. As a result, iron is a very poor indicator of trace nutrient levels.

Marcel, I hope you don't expect very many responses on this thread.


Roger Miller


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## TWood (Dec 9, 2004)

> quote:
> 
> Using tested iron levels as an indicator for other trace nutrients is an established practice. The chemistry of iron is different from the chemistry of other trace nutrients. As a result, iron is a very poor indicator of trace nutrient levels.


Hey Roger,

But what about not testing for iron, but simply dosing a micromix to a mathematically derived iron level? Don't the micros then fall into line behind the iron at the ratios they are present in the mix? Which does raise the question, which ratio is correct? I suspect different agricultural micromixes are designed to address regional soil conditions.

Edit: Snarky comment removed.









TW


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## Roger Miller (Jun 19, 2004)

> quote:
> 
> Originally posted by TWood:
> But what about not testing for iron, but simply dosing a micromix to a mathematically derived iron level? Don't the micros then fall into line behind the iron at the ratios they are present in the mix?


I can't think of a reason in the world why they should. That's why iron is a lousy indicator.

Iron hangs around in the water as long as it stays chelated then drops out of solution very quickly when the chelate breaks down. That breakdown rate depends on the kind of chelate, the pH, light spectrum and intensity, temperature and probaby a few other things. Very little of the iron actually gets used by plants. None of the other trace elements react the same way. Some of the trace elements have little tendency to react or precipitate and may stay in the water until plants use them. Copper, zinc, and nickle do not precipitate but might adsorb to surfaces -- whatever they do they certainly wouldn't do it at the same rate as chelated iron. Manganese tends to react a little bit like iron, but not under the same conditions and probably not at the same rates.

If you use iron as your standard (regardless of whether you test it or calculate it) then nutrients that are more conservative (less reactive) than chelated iron tend to build up in the water. Nutrients that are less conservative (more reactive) than chelated iron will tend to be depleted. You could get some real different behaviors out of two different trace mixes that are identical in every regard except the chelating agent used for the iron.

For the record, I use a commercial trace mix without iron and a commercial iron solution and I don't test or calculate a damned thing. Doses are determined from the manufacturer's recommendations and adjusted based on plant growth and on the principle that the dose of potentially toxic additives should be minimized.

I can dose iron rather freely because its toxicity is fairly low. In the case of other traces:

I dose a trace nutrient mix at the lowest rate necessary to avoids deficiency problems in most plants.

I try to avoid dosing things that the plants don't need. My tap water contains plenty of boron so I use a trace mix without boron.

I use substrate amendments to treat cases where one plant shows a deficiency that isn't shown by other plants in the same tank. That lets me avoid using higher doses.

I use small daily doses to avoid the high concentrations that result from a large dose delivered at longer intervals.

The possible behaviors of trace elements in the aquarium can vary greatly based on conditions in the aquarium. The need for dosing can be even more variable than the behavior of the chemicals. It's (to me) laughable to think that the trace nutrient needs of all aquariums can be satisfied just by using a trace mix and dosing to a predetermined iron level.

Roger Miller


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## TWood (Dec 9, 2004)

> quote:
> 
> It's (to me) laughable to think that the trace nutrient needs of all aquariums can be satisfied just by using a trace mix and dosing to a predetermined iron level.


Huh, well my apologies then to Marcel. More complexity is involved.

Except, doing just that DOES work (for me) so I'm not convinced that the additional layers of complexity are helpful.

TW - Bowing out to the experts...


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## m.lemay (Jan 9, 2005)

Roger: Thanks very much for the replys. I have a similar thread going over at theplantedtank site. Some of the things you've mentioned are enlightening. Unfortunately I don't have time to reply right now but I will in the next few days.


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## TWood (Dec 9, 2004)

As a follow-on, here's a comparison of products:

http://www.gpodio.com/fert_table.asp

An excerpt below. What's not clear to me is whether or not they are using the same method to calculate percentages. By weight, volume, or molecular weight? The ratios are way different, and may be explained by differences in the accounting method.

TW


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## m.lemay (Jan 9, 2005)

TWood: 
I apologize if I seemed "snarky" earlier. I didn't mean to be.The very reasons Roger has listed above are why I started this thread to try and get some more relevant science.The old PMDD theory of dosing micros till you get .1ppm of iron used to work for me too. 

Now I'm dosing what seems to be outragious amounts of micros while my java fern suffers from what looks like iron deficient chlorosis, and my E stellata is growing in pale, E parvulus is also starting to show signs of yellow. Its my speculation that its an iron deficiency since all my macros are kept up to snuff.

Roger: 
I just recieved some Iron Chelate 10% from GregWatson.com but I'm not sure how to come up with a dosing regimen because I'm not sure how to do the math (chemistry challenged). Do you know if 10% is by weight? Does 1 kilo(1000 grams) of this stuff yield 100 grams of iron? If that is the case, then I can do the math to get .1ppm concentration in my 75 Gal tank.How do you dose your iron chelate?

What I was thinking about doing is laying off the CSM+B and the flourish and just dose the iron chelate for a couple of weeks to see if things improve, what are your thoughts on that?

I'm not expecting tons of replys to this thread. I've been doing planted tanks for about 5 years and I'm a mod over at ThePlantedTank, I'm not new at this. I'm just trying to get some better science in the micro department, and hopefully everyone can benefit from this discussion.

Sincerely 
Marcel


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## m.lemay (Jan 9, 2005)

Heres an interesting article about some pretty specific iron behaviors when calcium interferes.Absorption of iron in plants


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## Roger Miller (Jun 19, 2004)

> quote:
> 
> Originally posted by Marcel:
> I just recieved some Iron Chelate 10% from GregWatson.com but I'm not sure how to come up with a dosing regimen because I'm not sure how to do the math (chemistry challenged). Do you know if 10% is by weight?


Analyses are almost always cited as weight percents. That's true for the iron chelate and for the analyses that Tom posted earlier. Unless something says otherwise, assume weight percent.


> quote:
> 
> Does 1 kilo(1000 grams) of this stuff yield 100 grams of iron? If that is the case, then I can do the math to get .1ppm concentration in my 75 Gal tank.


Sure.


> quote:
> 
> How do you dose your iron chelate?


In my two hungriest tanks I use SeaChem's Flourish Iron (ferrous gluconate) and dose about 0.33 ml/day per 50 gallons. In other tanks I dose Flourish comprehensive. I have in the past used ferrous gluconate tablets broken in pieces as substrate amendments. They work very well for targeted dosing.



> quote:
> 
> What I was thinking about doing is laying off the CSM+B and the flourish and just dose the iron chelate for a couple of weeks to see if things improve, what are your thoughts on that?


I'm not sure why you dose both flourish and CSM+B; I also don't know why you would stop dosing either of them while you experiment with the iron chelate.

The symptoms you describe sound like symptoms I might assign to an iron deficiency. But the iron level you report should be plenty. There are other things that cause similar problems. You might confirm that the problem is an iron deficiency by putting 1/4 of a ferrous gluconate tablet (from the vitamin section at the grocery store) in the substrate below one of the sick plants. If the problem is an iron shortage then that plant should quickly recover. Other plants probably will not.

I've heard other people report that the PMDD method worked at first then later stopped working. I don't really understand why that would be true. One possibility is that the tank and filter develop a bacterial population that consumes the chelate and precipitate the iron before plants get a shot at it. That kind of behavior happens all the time in things like waste treatment facilities but I've never heard it established as fact in an aquarium. There are other possibilities.

If there is such a specialized bacterial population it might be possible to correct the problem by switching to a mix with a different form of chelate. I think CSM uses EDTA, but TMG used DTPA. EDDA (I think it is) would be another option. Ferrous gluconate is also a possibility, but probably one that would require a different dosing proceedure to get the same result. The bacteria would be specialized to the original chelate but not trained to the new chelate, so the plants would have a better shot at the iron. After a while the bacteria would retrain to use the new chelate then you could switch back to the original. And on and on...

Anyway, that's barely educated speculation.

Roger Miller


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## aviel (Sep 12, 2004)

Marcel,

If you are using too much iron then *maybe* what you are experiencing is manganese deficiency -

See here http://www.spectrumanalytic.com/support/library/ff/Mn_Basics.htm

"Mn:Fe Balance: Soils high in available Iron (Fe), or high Fe applications can reduce Mn uptake. "

Manganese deficiency symptoms are similar to those of iron deficiency: "Because Mn is not translocated in the plant, deficiency symptoms appear first on younger leaves. The most common symptoms on most plants are interveinal chlorosis. Sometimes a series of brownish-black specks appear in the affected areas"

I had yellowish rotala green when I way too much iron in my tank.

And I said *maybe*.

Which leads me to my second observation. My gut feeling is that using CSM+B the amount of iron that I can add to my tank is limited. I did a survery here once and those who use flourish/flourish-iron dose ~ 0.2-0.4 ppm iron per day! (I know Roger, i know...) - my experiments for achieving this daily dose using CSM+B failed. Given my 2.6 wpg/PH=6.1/26-27C it seems like CSM+B can produce ~0.03 ppm per day ~max. Beyond that the chelate just accumulates to toxic levels and this is how I got the manganese deficiency.

I really would like to know if others are experiencing the same or I was the only one in the world trying to dose that much iron through a chelated mix.

And finally, I wouldn't restrict any thread to the "expert" level. U might discover that you can learn a thing or two from the experience of us newbies...

Aviel.


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## TWood (Dec 9, 2004)

> quote:
> 
> I really would like to know if others are experiencing the same or I was the only one in the world trying to dose that much iron through a chelated mix.


I've been using CSM+B for several years and haven't seen anything like you describe. However, I'm going for something closer to minimum rather than maximum levels. If you suspect a build-up of chelates to toxic levels (how do you know?) then why not do several water changes and then wait for iron deficiency to show up?

I do 20% weekly water changes and dose CSM+B when the new growth on h. difformis comes in pale. Then I dose it to get about 0.1ppm iron and wait. Depending on how thick the tank is, it can take a week or two before a new dose is needed. Keep a record and you'll see a pattern emerge.

More is not always better.

TW


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## aviel (Sep 12, 2004)

Twood,

If you dose to 0.1 ppm and you wait 10 days then for me it's 0.01 ppm per day. People are reporting 20X-40X times that amount. So yes - you won't have trouble and the chelate won't build up in your case.

I would like to dose iron like the insane fishfry/tsunami/you-name-them do. And I believe the chelate doesn't break that fast.

How do I know? I test for iron strangly enough...







And what do I say about test kits? I don't know - they can't measure the amount of iron that goes into the plant because that's a very very small number but they can tell me if my chelate is getting too big and if I exceed roger's 1 ppm inclusive toxic boundary.

Now a question to Roger!!!

The CSM chelate - if we focus on one molecule... - does it contain all the elements such that when it breaks - each element goes on its own way or is it that there is a chelate for iron and then a chelate for manganese and then a chelate for zinc and each of them breaks at a different pace? I mean - could it happend that using CSM - the iron is not broken from the chelate while the zinc is already depleted?

Aviel.


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## m.lemay (Jan 9, 2005)

After a bit of deductive reasoning on my part, I think its a magnesium deficiency. I haven't dosed magnesium in over a year, my tap water is pretty soft at 1-2 Dkh,1-2Dgh. I put a little crushed coral in the substrate a long 3 years ago so I wouldnt have to dose calcium carbonate at every waterchange. Between waterchanges the kh will vary from 3-6 dkh,my ph is locked in at 6.9 which gives me a variable co2 rate of between 15-about 25ppm CO2. Because my water is so soft I recieve next to zero Mg from tap water. My yellow symptoms are appearing in old growth java ferns and older Hairgrass which seems to be consistent with "Chucks deficiency symptom chart". I'm crossing my fingers. I just upped Mg to 10ppm calculated from chucks page using Epsom salt.

None of these symptoms appeared till just recently when I changed out my old 9325Ks GE bulbs a month ago,for new ones plus I added 2 more for a total of 330 watts over 75G. I also pumped up the CO2 recently to get my dwarf Hairgrass to spread and thicken.

I'll let you guys know how things pan out.

Anyone here using a Lamotte Iron test kit?

I think its time to change my profile to reflect my actual tank specs. Will do now.

I'd still like to see this thread continue as some very good informative material has surfaced here.


Thanks 
Marcel


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## Roger Miller (Jun 19, 2004)

Aviel, I think the chelate in CSM is EDTA. I'm not sure it makes much difference whether it's EDTA or something else.

It's probably only the iron that is chelated. Iron is added as a chelate because without the chelating ligand iron will not stay dissolved. It precipitates as an insoluble hydroxide. The other components of the mix are probably present as various kinds of soluble salts, e.g. copper sulfate, zinc sulfate, or ammonium molybdate. Because the other trace element (unlike iron) form salts that are readily soluble in water it isn't necessary for manufacturers to add them as expensive chelates.

Some of the metals do combine with EDTA to form metal-EDTA complexes. Boron and molybdenum do not. The non-iron complexes are generally weaker than chelated iron and those complexes may be found in the mix if the mix contains extra EDTA beyond that required to combine with the iron.

The iron-EDTA complex breaks down in light. That behavior is probably very important for the plants to get iron out of the EDTA. Other metal-EDTA complexes do not break down in light.

All-in-all there are very large chemical differences between the chemistry of chelated iron and the chemistry of most other trace nutrients, and that is true regardless of whether the nutrients are chelated or not. Manganese can behave somewhat like iron under some conditions but I don't know that those conditions are very important in aquariums.


Roger Miller


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## m.lemay (Jan 9, 2005)

A quick update: It does seem to be a magnesium deficiency. After dosing my tank to 10ppm mag, the plants started to pearl more vigorously and the leaves on my ferns are beginning to green up. I didn't think that I would see results this quick.

Roger:
You are truly knowledgeable in this area. Though you didn't tell me outright that its a Magnesium deficiency, for lack of details on my part, the things you posted had me thinking critically about what could be going on in my tank









Thanks 
Marcel


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## Roger Miller (Jun 19, 2004)

Marcel,

I'm glad that seems to be working out for you.

My tap water has a pretty odd and variable chemistry and on-again off-again magnesium deficiency is a problem that I learned to deal with about 7 years ago. All of my tanks are dosed with magnesium now whether the plants show deficiencies or not. I don't think of it much at all anymore, and when I do I don't think of it as fertilizing my tanks -- I think of it as fixing my water.

For 6 of the tanks I mix epson salt with the water I use for water changes. For the remaining tank I add epson salt along with the potassium nitrate dose after each water change. I'm not real picky about how much I add; enough to increase hardness in the tap water by a degree or so seems to be more than enough.


Roger Miller


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## Maurici (May 31, 2004)

Hi all,
I have two questions more for Roger: 
1- I would like to know if the breakdown of Fe chelates by light is due to photoxidation or photoreduction.
2- Do you know about the chemical breakdown of copper chelates (used as algaecides)? is also a question of light activation?
Thanks.
Maurici.


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## Roger Miller (Jun 19, 2004)

1) You could call it photoreduction or photoxidation depending on whether you're talking about the iron or about the EDTA.

The photochemical breakdown happens when the iron-EDTA combination adsorbs a photon of the correct energy (corresponding to a blue light, if I remember right). The photon energizes an electron on the EDTA molecule which then jumps to the iron. Electrons are sluts. The iron becomes reduced (an electron is added) and the EDTA molecule is oxidized (an electron is lost). The products are ferrous iron in solution and an organic molecule.

2) My understanding is that ferric iron chelates are the only chelates that are subject to photolytic breakdown. Copper chelates might be broken down by a number of other factors.


Roger Miller


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## Maurici (May 31, 2004)

Hi all, 
First, thanks a lot to Roger, the answer is so clear.
Another thing, have you any preference or recommendation on the timing for dosing nutrients? I'm thinking in a possible better results of adding the Fe taking on account the lights out.
Regards.
Maurici


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## Antonio Trías (Feb 4, 2004)

> quote:
> 
> Copper chelates might be broken down by a number of other factors.


Which were these factors Roger?, and not just for Cu also for the other non ferric chelates, are all them the same?

Thank you in advance


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## Roger Miller (Jun 19, 2004)

Maurici, I use ferrous gluconate rather than ferric-EDTA. I dose with iron and trace elements in the morning, but that is because of my schedule and not because of any chemical issues. I dose both iron and traces daily to reduce the temporary high concentrations that result from larger, less frequent doses. Doing things on a daily routine also helps me remember to get them done. Also, ferrous gluconate does not stay in solution as long as ferric-EDTA, so I do frequent dosing to avoid giving the plants longer periods without iron.

Antonio, non-ferric chelates are all different to one degree or another, but they have some common behaviors.

All metal chelates must coexist with some free metal ions in solution. The stronger the chelate is the lower that coexisting solution needs to be. Ferric-EDTA is a strong chelate so the coexisting concentration of ferric iron in solution is tiny. Most other chelates are much weaker than ferric-EDTA, so must coexist with more metal ions in solution. Any process in the aquarium that removes the free metal from solution causes the chelate to break down and release more metal ions to regain the necessary balance. Adsorption, precipitation, coprecipitation, complex formation and biological uptake all reduce the concentration of the metal and cause the chelate to break down more rapidly.

Increasing temperature generally increases the rate of reactions. Changes in pH will change the tendency of metals to adsorb, precipitate or form complexes and will also change the rate at which those reactions happen. The presence of reactive ligands in the water will also increase the rates at which the free metal is removed from solution.

EDTA (and I think other chelates) are organic acids and act as chelating ligands only over a certain pH range. Outside that range the chelate breaks down.

More speculatively, EDTA (and I think some other chelating ligands) could be fairly high grade bacteria food. They are small organic molecules with a nitrogen content. A well-adapted bacterial community might break down added chelates for their calorie and nutrient content. That requires that the bacteria also somehow avoid poisoning from the attached metal.

Also, I wonder if UV radiation might accelerate the breakdown of chelates. This would be through a mechanism different from photolysis of ferric chelates. In the case of other metal chelates the metal ion would not act as a convenient receptor for an electron.


Roger Miller


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## Antonio Trías (Feb 4, 2004)

Thanks Roger







.

And last: Do you know any open web site were to go deeper on the understanding of these kinetics?


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## Roger Miller (Jun 19, 2004)

Antonio, there is a lot of information freely available on the web, but most of it is very technical and it is necessary to work through a lot of irrelevant material to find the few bits of important information. There is a definite shortage of summary information.

One interesting source of information is

http://www.coldcure.com/html/stability_constants.html

The site summarizes a lot of information on chelate chemistry at a level that -- while still very technical -- can be understood without a graduate degree in chemistry.

If you are so inclined, there is a great research level computer program from the USGS called PHREEQC that is designed for calculation of chemical equilibrium in complex systems that can include kinetic effects. The program is available at

http://wwwbrr.cr.usgs.gov/projects/GWC_coupled/phreeqc/

The data that accompany the program include equilibrium constants for EDTA and some of its metal complexes. There is also some important kinetic data available in its references and documentation. Unfortunately the documentation is quite difficult to follow.

I used PHREEQC while I was trying to understand the environmental behavior of ferric-EDTA. It was very useful.

Roger Miller


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## Antonio Trías (Feb 4, 2004)

Thank you again Roger, and don’t worry about too much technical information. I’m not a chemist, but because my formation, I have some knowledge on biochemistry 

Best Regards
Antonio Trías


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## wschalle (Jan 26, 2005)

I personally use h. polysperma as my iron indicator. It lets me know within a day, and the colors range between pure green to reddish green to brilliant red with white veins.

I'm certainly no expert, but I generally add .25 ml of iron to my 10gal whenever new growth on the polysperma isn't red.


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## AquaLung (Dec 8, 2004)

> quote:
> 
> Originally posted by Roger Miller:
> ...My tap water contains plenty of boron so I use a trace mix without boron....


I just had my water tested and I have 0.14 mg/L Boron. Is that considered high or low for a high-light CO2-injected planted tank?


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## Roger Miller (Jun 19, 2004)

I'm not sure where the low end for boron concentration is. I expect that 0.14 mg/l should be fine -- neither high nor low.


Roger Miller


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## AquaLung (Dec 8, 2004)

> quote:
> 
> Originally posted by Roger Miller:
> I'm not sure where the low end for boron concentration is. I expect that 0.14 mg/l should be fine -- neither high nor low.


Thanks. Do you think a Sodium concentration of 34 mg/L is detrimental to plant growth?


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## Roger Miller (Jun 19, 2004)

> quote:
> 
> Do you think a Sodium concentration of 34 mg/L is detrimental to plant growth?


No. Not at all.

Roger Miller


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