# [Wet Thumb Forum]-Iron dosing



## Kristian (May 19, 2003)

I've been dosing a 30g with Seachem's Iron and it seems that no matter how much I put in, I can't get it to register on my Seachem test kit. I know the reagents are good because tests with the reference sample work fine. I can add 6ml and the next day none shows up on the test. Understanding that all tanks are different, what's a typical amount used for this size tank? Thanks!

Kristian Anderson


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## Kristian (May 19, 2003)

I've been dosing a 30g with Seachem's Iron and it seems that no matter how much I put in, I can't get it to register on my Seachem test kit. I know the reagents are good because tests with the reference sample work fine. I can add 6ml and the next day none shows up on the test. Understanding that all tanks are different, what's a typical amount used for this size tank? Thanks!

Kristian Anderson


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## Rex Grigg (Jan 22, 2004)

It would help if we knew what your tank size was.







Other than that don't waste your time testing for iron. I just dose the tank and don't worry about it. Iron test kits are not very accurate or reliable.

Moderator










American by birth, Marine by the grace of God! This post spell checked with IESpell available at http://www.iespell.com

See my Profile for tank details.


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## Dr.T. (Jul 23, 2003)

I recently started a similar discussion - 
http://aquabotanicwetthumb.infopop.cc/groupee/forums?a=tpc&s=4006090712&f=9156020792&m=9096019393

Although I can measure Fe immediately after addition - several hours later, I cannot.

Jeff (Dr.T.)
---------------------------
Tank info in profile
29 gallon tank
65 gallon tank


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## Roger Miller (Jun 19, 2004)

The thread that Jeff linked to contains quite a bit of discussion on the same topic, so I'll just give a synopsis of my point of view.

1) Don't try to manage iron levels with iron test kits. It isn't necessary. It works poorly at best. It's almost always a frustrating waste of time.

2) Seachem's iron does not stay in solution very long. The best way to dose with Seachem's iron (or any other iron gluconate) is to use small, frequent doses.

Last spring I started dosing my big tank daily with Seachem iron at the rate of 1 ml/day/75 gallons. The results were excellent. The size of the dose should be adjusted for conditions in your tank. The doses should probably be done at intervals of 2 days or less. Once/day is convenient.

Roger Miller

"The indispensible first step to getting the things you want out of life is this: Decide what you want" -- Ben Stein

[This message was edited by Roger Miller on Fri September 19 2003 at 04:09 PM.]


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## imported_George (Mar 28, 2003)

I have been testing for iron daily using two brandname test kits, Seachem and Hagen, for the last three weeks. I just wanted to see if there was a detectable and repeatable difference in the relative amount of iron that was indicated by each test kit....totally unsceintific. Results of these observationss are a subject for another thread, but it soon became apparent that relative levels of detectable iron did seem to "deplete" in a matter of hours not days. Twice, I added enough Seachem Iron to indicate a high ppm. I considered a "high ppm" as relative to the indicated ppm on the test kit color scale and did not assume that the test resulted in the "actual" ppm iron, i.e. 0.6 ppm (high) vs. 0.05(low). Even at the high ppm level, within 24 hours it dropped to low or even zero.

Considering the apparent short-time period (hours not days) that iron gluconate may be available to be utilized by plants, including algae, and a "normal" dosing level, can we assume that "excess iron(gluconate)" will not be the single cause for the sudden appearance of algae, i.e. thread, etc, in a heavily planted and CO2 supplemented aquarium?? Too simplistic of a conclusion?

George

[This message was edited by George on Sat September 20 2003 at 05:44 AM.]


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## Roger Miller (Jun 19, 2004)

George,

Iron levels as lows as 0.06 parts per *billion* are sufficient for plant growth, so having the level drop below 0.05 ppm may not be a meaningful measure.

That's just one problem with iron testing. Another is that commercial tests have a limited ability to measure chelated iron. We generally don't know whether our test results are measuring all of the iron, just the uncomplexed iron, or something in between. 

Moreover, with strong chelates (EDTA for instance) the chelated iron isn't available to plants, but with weak chelates (gluconate) the chelated iron probably is available to plants. So the interpretive problems are large.

All in all, we are just better off getting our iron dosing clues directly from the plants rather than trying to depend on test kits.


Roger Miller

"The indispensible first step to getting the things you want out of life is this: Decide what you want" -- Ben Stein


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## imported_George (Mar 28, 2003)

Roger,

I just spent an hour preparing a reply to your post. My reply stated some of the early assumptions I used relative to the use of iron test kits to at least identify the "presence" or "absence" of chelated iron. Also, some of the shortcomings of using the comparative test method, solution color vs. scale color, that result in a subjective interpretation of the results even if testing for iron was somewhat accurate....depends on the "eye" of the beholder. These shortcomings also apply to other types of test kits...pH, NO3, etc. I LOST THE DAMN THING WHEN I TRIED TO POST IT. I will just leave it with the following comment.

Your reply stating how small an amount (0.06 billion parts) of iron can be utilized by plants and the uncertainty of what is exactly being measured with iron test kits clarifies why you and others recommend not using the test kit. I was not sure if these recommendations were due to the inacurracy of the test kits to measure the actual difference in ppm chelated iron or the kits just do not measure what we think it measures. You have filled in the blank spaces. Thanks again.

George

[This message was edited by George on Sat September 20 2003 at 01:12 PM.]


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## Antonio Trías (Feb 4, 2004)

I believed, that the stability of the iron gluconate was lower than the EDTA or another complex, but i find this information on a very serious web (unfortunatelly is on spanish)Fe-Gluconate , but is easier to read the table more or les on the end


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## anonapersona (Mar 11, 2004)

> quote:
> 
> Originally posted by Roger Miller:
> All in all, we are just better off getting our iron dosing clues directly from the plants rather than trying to depend on test kits.


I think I've forgotten WHAT those clues are! What should I look for?


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## Roger Miller (Jun 19, 2004)

Anonapersona,

The main symptom is interveinal chlorosis on new growth. Interveinal chlorosis is when the veins in the leaves are green, but the tissue between the veins is lighter; light green, yellow or even white. In grass-like plants the whole leaf is light-colored.

Unfortunately, several other nutrient shortages have the same symptoms. You can tell if iron is causing the problem just by increasing the iron dose. For well-rooted plants I found that one pretty dependable way to test for an iron shortage is to break up an iron gluconate tablet (from the vitamen isle at the grocery store) and push a crumb of it into the root zone of a plant. If it's an iron problem then that plant should be cured. Other plants with the same symptoms elsewhere in the tank should still have the symptom.

Increasing either the size or frequency of the iron dose is the easiest solution, but if you have consistent problems or don't want to increase the dose then you might try something else. For instance, you could use root feeding with iron tablets, add soil to your substrate or replant the affected plants in pots with soil. 


Roger Miller

"The indispensible first step to getting the things you want out of life is this: Decide what you want" -- Ben Stein


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## skunky (Jun 22, 2003)

I'm finding this Iron dosing business a little confusing! A while ago my reading led me to believe that Iron EDTA was the most appropriate form to use.

Sorry to be a pain Roger but could you explain to me why this is not the case. I have just started using Kent's Fe Botanica once a week @ my 50% water change. Is it because the Fe is locked up to well in this EDTA chelate which plants find hard to utilise?

Which commercial Fe product would you recommend?

Many thanx

Stuart

'Nothing is that easy'


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## Roger Miller (Jun 19, 2004)

Skunky,

Years of successful use has shown that EDTA is good source of iron. I didn't mean to imply otherwise.

There are large differences in the way the Fe-EDTA works and the way that Fe-gluconate works and that means that they can't be used in the same way.

The iron in Fe-EDTA is not biologically available. The Fe-EDTA complex has to be broken down before plants can get to the iron. The complex breaks down slowly over a period of time, creating a low concentration of biologically available iron. When the iron is released it remains available for only a brief period of time before it either precipitates or is again bound into a complex. As a result, the actual amount of iron available to the plants is *much* lower than the total amount of iron in solution.

The amount of EDTA-iron that is biologically available is not constant. It depends on the amount of complexed iron in the water, on teh intensity and spectrum of the light in your tank, on the pH and on the presence of other complex-forming compounds in the water. That is part of the reason why people report variations in the amount of EDTA-complexed iron that their tanks seem to need. For instance, while most people have found that their plants get enough iron when their kits measure 0.1 ppm or iron, Tom Barr found that he had to keep 0.7 ppm iron in his tanks. Add to that the difficulty of getting a consistent measurement of EDTA-complexed iron from any test kit. All things considered I think it's pretty remarkable that there is or was ever a consensus about how to use EDTA iron.

Using iron gluconate is a relatively simple proposition. It is biologically available and breaks down quickly in water. You use frequent small doses that are adjusted to meet the plants requirements. Testing is futile, so it's best not to waste your time testing. Unfortunately, Seachem doesn't seem to acknowledge the differences between EDTA and gluconate and (for marketing reasons) their printed instructions on the label are based on common usage with EDTA-iron.

I also like to use Fe-gluconate as a substrate amendment. You can do that with Fe-gluconate tablets from the pharmacy or grocery store.

All in all I prefer iron gluconate. Using it is a simple, non-mysterious process and the results have been good. Except for the substrate dosing thing, you can get the same results from iron-EDTA.


Roger Miller

"The indispensible first step to getting the things you want out of life is this: Decide what you want" -- Ben Stein


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## skunky (Jun 22, 2003)

Many thanx for your reply Roger, most helpful!

'Nothing is that easy'


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## Vicki (Jan 31, 2003)

Well, Roger, I liked the sound of your daily iron dose and I had a bottle of Flourish Iron on hand, so I decided to try it in my 30 gallon; started this past Sunday. I started peat filtration on the same day for my apistos--and I don't know whether it's the iron, the peat or a combination of both, but I'm amazed at the way the plants are responding. I had just topped and replanted my nesaea, and in four days it's back to the top of the tank. The new leaf whorls on the baby tears are twice the diameter they were before, and the ludwigia brevipes has increased its growth rate, too. All the plants were doing well before, and showed no signs of iron deficiency, but I'm pretty impressed with the results! I think the nesaea and baby tears in particular like the lower ph and the tannins, but I think I'll stick with those small daily iron doses. Thanks for sharing that!

http://www.wheelpost.com


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## Roger Miller (Jun 19, 2004)

Vicki,

I'm glad that you got such a great result, whatever the cause









Roger Miller

"The indispensible first step to getting the things you want out of life is this: Decide what you want" -- Ben Stein


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## Vicki (Jan 31, 2003)

LOL! Now I'm sorry I started both at the same time, I don't know what's made the difference! I'll have to experiment in another tank that isn't peat filtered and see what happens there.

http://www.wheelpost.com


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