# [Wet Thumb Forum]-Depleting Fe



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

I have a Hagen Fe test kit, and I measured my Fe as non-detectable by the kit, one day, and responded by adding enough to get me to around 0.3 ppm Fe (using Flourish Fe). The Hagen kit verified this. The following day, the test kit showed no Fe. Again I dosed accordingly. 

I understand Fe is difficult to measure, but what is happening? Are my plants eating the Fe that fast?!

65 gallon 192W VHO fluorescent, pH 6.8, KH 6.0, GH 13, additional K added during water changes - 15% weekly.

Troubled...

Jeff (Dr.T.)

Tank info in profile


----------



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

I have a Hagen Fe test kit, and I measured my Fe as non-detectable by the kit, one day, and responded by adding enough to get me to around 0.3 ppm Fe (using Flourish Fe). The Hagen kit verified this. The following day, the test kit showed no Fe. Again I dosed accordingly. 

I understand Fe is difficult to measure, but what is happening? Are my plants eating the Fe that fast?!

65 gallon 192W VHO fluorescent, pH 6.8, KH 6.0, GH 13, additional K added during water changes - 15% weekly.

Troubled...

Jeff (Dr.T.)

Tank info in profile


----------



## perrush (Feb 24, 2003)

the question about what those Fe testkits measure, how they work, and so on, would have been my next question to ask (@ roger ??) (after composing that trace mix)

But know that you've come up with it, Roger might answer it already









--
English isn't my native language, but I guess you already noticed that ))
--

Perrush


----------



## Ron Nelson (Apr 2, 2003)

I'm not sure I can explain this with all the details but as I understand it basically FE is very unstable in the aquarium. And the test kits don't work very well accourding to others on this board. The concensus seems to be that you dose more than enough to make sure you don't see any symptoms of a lack of FE and ignore your test kit. If I got any of that wrong I'm sure Rex or someone else will chime in with corrections.









Ron


----------



## Roger Miller (Jun 19, 2004)

Dr. T,

We'll just put aside any question about just what the kit is measuring. I don't think that is the problem.

What you are finding is the same thing that everyone finds when they try to follow the directions on the bottle. You can't maintain 0.1 ppm of iron. The iron in Flourish and Flourish Iron just does not stay in solution.

I talked to Greg Morin (Seachem) at the AGA conference last year and asked how they arrived at the 0.1 ppm iron recommendation. He said they recommended that level because it was the common recommendation on APD. They didn't do any research to support their recommendation. If they did they would have figured out that you can't do that with iron gluconate.

The prevailing experience with iron dosing is with iron EDTA, which is much more stable than iron gluconate and tends to keep the iron in solution longer. The common experience that iron needs to be kept at about 0.1 ppm was based on the behavior of EDTA; iron gluconate is very different.

The best way to dose iron with Seachem products is to use frequent, small doses. Don't use a test kit. Start by using Seachem's recommended dose weekly and adjust from there based your observation of the plants.

I dose once or twice a week using Seachem's recommended dose of 1 ml/10 gallons. In one of my tanks I recently started dosing daily at 1 ml/75 gallons -- a considerably smaller dose. The jury is still out on that experiment.


Roger Miller


----------



## Rex Grigg (Jan 22, 2004)

Even using iron chelated with ETDA I have a hard time getting consistent test results.

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.


----------



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

I forgot to mention I run DIY CO2 24/7... Regardless - Roger, so if the Fe doesn't stay in solution, is it falling out of the chelator and is no longer available to the plants? I should then be able to check for non-chelated Fe using the same kit. Or rather is it all being consumed by the plants, but broken down as the plant requites it?

How will an iron defficiency present itself? I have lots of stem plants (Hygro Scarlet), swords and crypts - among other things.
Rex - do you just does according to manufacturer recommendations?

Jeff (Dr.T.)

Tank info in profile


----------



## Roger Miller (Jun 19, 2004)

> quote:
> 
> Originally posted by Dr.T.:
> if the Fe doesn't stay in solution, is it falling out of the chelator and is no longer available to the plants? I should then be able to check for non-chelated Fe using the same kit. Or rather is it all being consumed by the plants, but broken down as the plant requites it?


When iron is released from the chelate (for whatever reason) it will stay dissolved only very briefly. It quickly forms insoluble hydroxides and precipitates. After that the iron can't be measured and it generally can't be used by plants.



> quote:
> 
> How will an iron defficiency present itself? I have lots of stem plants (Hygro Scarlet), swords and crypts - among other things


Iron deficiency appears as interveinal chlorosis -- green veins, with yellow leaf tissue in between -- that shows up first on new growth. Unfortunately several other nutrient deficiencies appear the same way so the symptom isn't diagnostic. Some plants are much more susceptible to iron deficiency than others. Some people report that Hydrocotyle leucocephala is usually the first plant to show an iron deficiency.
.
It's difficult to describe, but I think when plants are well-supplied with trace nutrients (including iron) their growth is robust and their colors -- both red and green -- are rich and vibrant. It is probably that overall appearance that triggered Claus Christensen to comment that all the tanks he saw while visiting the San Francisco area a few years ago were low on trace elements.

I don't think you can see this difference in online photos. There are too many issues with white balance, exposure, resolution and color rendition. You actually need to see plants grown under different conditions.

Roger Miller


----------



## Rex Grigg (Jan 22, 2004)

I'm working with an iron chelate mixture of my own right now. And I am still working on the dosing. I'm not showing any iron deficiency at all. In fact I have gotten a bit too much in the tank due to the sudden increase in the green spot algae.

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.


----------



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

So, Roger, if the Fe is being converted to hydroxides and inorganic Fe's, I would assume these are no longer available to the plants. So this would indicate more frequent dosing is required - yeah or neah?

Jeff (Dr.T.)

Tank info in profile


----------



## Roger Miller (Jun 19, 2004)

Yeah. Small, frequent doses.

Roger Miller


----------



## wetmanNY (Feb 1, 2003)

How about supplementing chelation instead of supplementing Fe? Aren't organic chelators, such as polyphenols, which include tannins and humic substances, more stable as chelators than, say, gluconate?

In acidic, low-oxygen levels of the substrate, Fe(II) and Fe(III) may remain in solution, I understand. Do ferric hydroxides re-dissolve under certain conditions? Or are they "lost and gone forever" like Clementine?


----------



## Roger Miller (Jun 19, 2004)

> quote:
> 
> Originally posted by wetmanNY:
> How about supplementing chelation instead of supplementing Fe? Aren't organic chelators, such as polyphenols, which include tannins and humic substances, more stable as chelators than, say, gluconate?


I don't know if those complexes are more stable than ferrous gluconate or not. More to the point, why do you want it complexed? Strongly complexed iron generally isn't useful to plants. Chelates are only used as a means of getting the iron to the aquarium. Once it's there the complex has to break down before the iron is useful.



> quote:
> 
> In acidic, low-oxygen levels of the substrate, Fe(II) and Fe(III) may remain in solution, I understand. Do ferric hydroxides re-dissolve under certain conditions? Or are they "lost and gone forever" like Clementine?


They can redissolve, but I don't know if the kinetics are very favorable. Plants can even get ferric hydroxides to redissolve, but that may require an iron deficiency stress response before it happens.

Roger Miller

[This message was edited by Roger Miller on Sun August 17 2003 at 07:19 PM.]


----------



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

Interesting discussion, all - thanks for the insight.

Jeff (Dr.T.)

Tank info in profile


----------

