# [Wet Thumb Forum]-Fe test



## Chousal (Feb 8, 2004)

Hi somebody has used the Red Sea Fe test?

I think it doesnt mark at all

please excuse me my english is not very well

Saludos...

Acuariofilia most not be costly.


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## Chousal (Feb 8, 2004)

Hi somebody has used the Red Sea Fe test?

I think it doesnt mark at all

please excuse me my english is not very well

Saludos...

Acuariofilia most not be costly.


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## Roger Miller (Jun 19, 2004)

Chousal,

I had a Red Sea kit years ago. When I used it on my tank it read nothing. I dosed more iron and it still read nothing. I dosed more iron and it still read nothing. Finally I took a jar of water and added enough powdered DTPA-chelated iron to the jar to turn the water yellow. I tested that and still the test showed nothing.

I threw the test kit away.

Roger Miller

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_"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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## Chousal (Feb 8, 2004)

Thank you veeery muuuch

I thougth i was crazy !!!!

would you recomend some?

Saludos...

Acuariofilia most not be costly.


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## dennis (Mar 1, 2004)

I have the same test kit. Seems to work well fo rme and be fairly accurate, posssibley to accurate. I find it to be fairly useless nore the less. Just watch some of your stem plants. My L. repens and D. diandria tell me when to dose as do some common sense from my no3 tests. I am sure others can give you more plants that also indicate fe levels based on the growth and color.

Dennis Dietz

http://webpages.charter.net/dennisdietz/Aquatic%20Endeavors.html


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## Roger Miller (Jun 19, 2004)

Chousal,

I usually tell people not to waste good money on iron test kits.

Roger Miller

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_"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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## Planted Engineer (Jan 15, 2004)

Roger,

Maybe you should revise your opinion on Iron test kits... I had the very same problem with a JBL test kit. I e-mailed them and they told me that my series number is way too old... at that time they didn't know how to free the iron from the chelation... But beyond some number the kit works. I replaced this week for free and tested... Fe=0.4 - hope it's not too much till next water change









PE.


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## Roger Miller (Jun 19, 2004)

PE,

The ability to measure chelated iron is of dubious value. Plants use only uncomplexed iron. Signficant concentrations of biologically available iron are on the order of 1x10-8M to 1x10-6M depending on who you read. That's 0.000056 to 0.0056 mg/l. Iron is a trace element. Plants use it in small quantities.

Can you get your kit to register fractional parts per billion of uncomplexed iron?

Roger Miller

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_"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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## Planted Engineer (Jan 15, 2004)

Roger,

I think that Fe test kits still provide useful information. I consider the chelated value as an 'Fe stock size'. If at the beginning of the week it reads 0.2 ppm and at the end of the week it reads 0.1 and I know how much to add in order to get back the 0.2 ppm then I know that plants (and algae...) are consuming the Fe. But if I discover that at the end of the week I have 0.2 ppm then I should guess that growth is stuck, that something else is missing - maybe nitrogen, maybe potassium, maybe you-name-it - it's a clear indication that something is going wrong. Sears & Collins actually suggested to set the Fe value and then make sure that it is decreased. 

PE.


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## Roger Miller (Jun 19, 2004)

PE,

If the test kit analyses chelated iron then you're right, it does give you a stock size. The next problem is that the amount of plant-available iron that you get from that stock varies from one kind of chelate to another, varies with the amount and kind of lighting you have and probably varies with a number of other biotic and abiotic factors as well.

If you're using Flourish Iron then you have additional problems with testing. Lots of people have found that they can dose in the morning and the iron is gone in the evening. Dosing enough to keep it at Seachem's recommended level requires that you use a rediculous amount of iron.

Plant use of iron is a very small part of the total iron loss from "stock." Most of the iron is oxidized and precipitates. As a result, when you see the stock decline (or not) that observed effect is not an indicator of whether or not your plants are consuming the iron.

In the end, your guess is as good as a test. An educated guess based on observations of your plants is probably better than a test.

Roger Miller

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_"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 Wed February 11 2004 at 06:18 AM.]


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## Planted Engineer (Jan 15, 2004)

Roger,

My assumptions were that

1) JBL test kit measures both chelated and free iron.

2) Under reasonable conditions (for example for flourish KH<=6) the Iron is consumed only by the plants.

if (2) is not correct then I was wrong.

But just to make an end to this story - Where does the iron go??? Is it being accumulated to an 'infinite rust' over the time? flushed during water changes? Broken by bacteria in the substrate and become available eventually to the plants?

(Please don't mention ferrous gluconate or seachem as they don't really have a 'stock'...)

PE.


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## Roger Miller (Jun 19, 2004)

> quote:
> 
> 1) JBL test kit measures both chelated and free iron.


That may be a reasonable assumption. I would be curious to know how they arrange to break down all of the possible chelates.



> quote:
> 
> 2) Under reasonable conditions (for example for flourish KH<=6) the Iron is consumed only by the plants.
> 
> ...


Plants use very little iron. At least 99% of the iron you add precipitates as iron oxyhydroxides or is adsorbed on surfaces. Some of that settles into the substrate, some of it ends up in the filter, some of it clings to detritus in the tank and gets cleaned out.



> quote:
> 
> Broken by bacteria in the substrate and become available eventually to the plants?


 Some iron-stressed plants can use precipitated iron. That is a response to iron deficiency; plants have to be stressed before they expend the resources it takes to get iron out of the precipitated hydroxides.

Bacteria may convert it to plant-usable forms if you arrange for the right conditions. That means oxygen-poor conditions in the substrate. Under the same conditions bacteria will also make iron available from the substrate materials (flourite, laterite, clays, etc) and from mulm.

Roger Miller

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_"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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## Chousal (Feb 8, 2004)

I have had good results, just having the Fe detectable.
if you don't make the test the only way to know if it isnt present its the clorosis. am i wrong?

Saludos...

Acuariofilia most not be costly.


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## Roger Miller (Jun 19, 2004)

You are right.

Roger Miller

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_"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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