# Best form of Fe?



## BryceM (Nov 6, 2005)

This gets brought up now and again, but I'm wondering about current thoughts with regards to iron. It seems to me that most people who use Flourish are adding additional iron in one form or another, usually with Flourish Fe. It seems that those who use TMG usually don't use additional iron. I have no basis for guessing what those who use CSM+B mixes do.

My understanding is that Flourish contains iron gluconate, while TMG contains a more highly bound form of iron, complex with a chelating agent. People have gone back and forth about the energy the plant needs to expend to assimilate each type of iron, but a consensus on this point hasn't been reached. It seems to me that you need much larger quantities of the gluconate form to acheive the same effect in the tank. I'm wondering what everyone else has to say about it..........


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## Laith (Sep 4, 2004)

I think that the dosing of Flourish Fe in addition to Flourish is a requirement, not an option. Flourish is made up mainly of trace elements with very little Fe. Here's what Seachem told me:

"*Flourish is designed as a trace element supplement*. When following the dosage on the bottle the following is how much iron you are adding with each product

Flourish has 0.0064 mg/L (ppm) of Iron per 5 mL in 250 L
Flourish Iron has 0.2 mg/L (ppm) of Iron per 5 mL in 200 L

So as you can see Flourish Iron adds a lot more Iron. Our dosing chart recommends to add 1 cap of Flourish Iron per 50 gallons every day."

They're not very clear about this and most people assume that Flourish Fe is just for extra Iron while in fact the two products need to be used together to get adequate levels of Fe and traces. At least that's what I've understood.

So the standard dose of Flourish adds 0.0064mg/l of Fe while the standard dose of TMG (5ml per 50l) adds 0.07mg/l of Fe. That's more than a 10x difference.

Regarding the chelators, it seems that the chelator used in TMG is better in harder water than the gluconate. I have tanks setup with both 5KH and 15KH and have been testing the TMG on the 15KH tank. So far I think that the TMG works better in the higher KH water than Flourish does: no precipitate/cloudiness and plants look more like the plants dosed with Flourish/Flourish Fe in the tank with a KH of 5. Then again, the differences are subtle (except for the precipitate).


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## BryceM (Nov 6, 2005)

Laith, the following is copied from a post that I made earlier in the "math behind the fertilator" thread. I suspect that the Seachem rep. that replied to your inquiry made a math error.

If this is true then regular Flourish contains almost exactly the same quantity of iron as TMG, albeit in a different form. My own personal bias leads me to suspect the chelated form in TMG is much more available to the plants. The effect of KH on this is something I hadn't considered. Interesting.......



guaiac_boy said:


> *Seachem**'s Flourish lists 0.32% soluble iron, Seachem's Flourish Iron lists 1% soluble iron. What does this mean in PPM?*
> 
> Let's assume you dose Flourish per their recommendations (5 ml per 250 liters per week).
> 
> ...


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## banderbe (Nov 17, 2005)

I think it depends on the amount of TMG people use. The bottle says to use more until your plants green up. I don't want to do that given how much it costs so I supplement with Flourish fe.


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## Laith (Sep 4, 2004)

I thought that their calculation was incorrect too. When I queried it, they replied the following:

"0.0064 is correct. Here is the formula.

1000vP ÷V = C
where v = volume being dosed in mL
P = % of that element in our product
V=volume of water being added to in mL
C=final concentration of element after dosing
You just need to pull "P" from each of our labels for each element of interest and plug it into the equation to solve for "C"

(1000 x 5 x 0.32) ÷ 250000 = 0.0064"

Your calculation makes more sense (.0032*5/250) but I haven't had the time to go through their version... I suspect that they used the percentage incorrectly.

So if it's 0.064mg/l in a dose of Flourish, then the difference that I see between the two products in low and high KH water must have something to do with the chelator. Their reply re the precipitation was the following:

"The gluconate works equally well in both soft and hard water... The fact that you are getting a white cloudiness would indicate that you are precipitating out the iron... In waters with an extremely high phosphate or carbonate hardness Iron can precipitate out... Its not a reaction of the Gluconate but of the iron itself."

So I'm still confused; can Fe bind with carbonate to produce the precipitate? If so, why don't I get the same issue with TMG in high KH? I'm assuming that it's because the chelator is stronger and doesn't allow the Fe to separate and bind with whatever its binding with to cause the precipitate...


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## plantbrain (Jan 23, 2004)

edit


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## BryceM (Nov 6, 2005)

Isn't it possible to buy bulk iron gluconate, or various forms of chelated iron? It seems to me that I dose every other nutrient from raw chemicals at great savings. Is there anyone out there doing this?

I bring this up because lately it seems like my tank is requiring ever-increasing doses of Flourish iron to prevent chlorosis. I'm using 1/2 ml per gallon per week, but maybe I need more. I believe the deficiency to be iron-related because improvement with larger dosing is readily apparent in the fast-growing stemmies. My KH is only 4 but my phosphates have trended up a bit - I believe the city is adding more to the water. Maybe I'm loosing more to precipitation than previously.

In any case, I recently ran out of Floruish and I've got some TMG on the way. I'll see how it works over the next few weeks.


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## MrSanders (Mar 5, 2006)

> Isn't it possible to buy bulk iron gluconate, or various forms of chelated iron? It seems to me that I dose every other nutrient from raw chemicals at great savings. Is there anyone out there doing this?


 Did you check Greg's site? I bought some from him a while back, it is a chelated form of Iron... though Im not sure of the chelater used off hand. When I first got it I worked out how much it would take to make it the same concentration as Flourish Fe.... and I dont remember exact numbers but it ended up working out to be a few bucks per 500 ml bottle.... a HUGE price break, espically when large amounts of Fe are being used.


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## banderbe (Nov 17, 2005)

Guaiac boy, try dosing daily instead of weekly. The seachem support person in the Seachem forum says it gets used up rather quickly.

I dose 2.5 ml per day in my 29 gallon.


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## plantbrain (Jan 23, 2004)

edit


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## BryceM (Nov 6, 2005)

I do dose 3X per week, which I should have been more clear about. The total for the week is about 0.5 ml of Flourish Fe/gallon.

Tom, have you noticed a need to supplement iron in addition to TMG?


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## banderbe (Nov 17, 2005)

I think Tom just doses TMG to levels where he is confident he's getting enough iron. That seems too expensive to me so I supplement my TMG dosing (3 ml daily) with Flourish Fe.


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## Mjproost (Nov 17, 2005)

Actually, TMG is a little cheaper than Flourish Iron if purchased in the large bottles. 

What are people's experience with Greg's Iron Chelate?

I have some and I just starting using it today. I mixed it 3.53 ounces to 1 liter of water. I dosed it just like I would dose Flourish FE, and it turned the water a noticeable iron color that did not happen with Flourish Fe. I do not have an Iron test kit, and I cannot afford the money necessary to get an accurate one. I am also chemistry challenged, so I do not really know how to calculate how much I am adding. 

Does anyone know the concentration of the solution I made with 3.53 ounces in one liter of water?


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## banderbe (Nov 17, 2005)

But you don't need as much of Flourish Fe to attain the same level of iron that you would need of TMG. That's how I was thinking of it anyway, though admittedly I haven't sat down to punch the numbers.


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## czado (May 26, 2005)

> Does anyone know the concentration of the solution I made with
> 3.53 ounces in one liter of water?


 Assuming 10% Fe chelate

3.53 ounces = ~100 grams

100g Fe chelate * (.1g Fe/g Fe chelate) / 1L = 10g Fe/L 
(same as 10mg Fe/mL, a nicer unit)

To calculate ppm (mg/L) from your dose:
(tank gal * 3.77L/gal) / (10mg Fe/mL iron mix * mL dose) = Fe ppm

Lets rearrange this to say you want to know how many mL to dose to get .2ppm Fe in 20gal.
(target ppm * tank gal * 3.77L/gal) / (mg Fe/mL iron mix) = mL dose to reach target ppm

(.2 ppm * 20gal * 3.77L/gal) / (10mg Fe/mL) = ~1.6 mL

It is a rich mix, and unless you have a large tank you should consider diluting it.

banderbe,
I believe part of the argument in favor of TMG is that you don't need as much iron as other brands because it uses a better chelator. I dosed to .3ppm Fe every other day with Greg's old CSM+B+Extra Fe mix, but am under .2ppm/wk (~.06ppm per dose) with TMG, and my plants still look decent, for example.


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## banderbe (Nov 17, 2005)

czado, you are saying 1.6 ml of TMG in 20 gallon tank yields 0.2 ppm Fe?

That seems to disagree with this TMG iron calculator:

http://www.fishfriend.com/fertfriend.html

It claims that 1.6 ml of TMG in 20 gallons would yield 0.0147 ppm.


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## Mjproost (Nov 17, 2005)

czado-

Thanks for doing the math. I am definitely going to dillute it.

BTW- Its good to know that a rather extreme overdose of Iron does not cause algae. For the past week, I dosed 5 ml TMG and 5 ml's of that solution I made 3 times. No algae, and I do not see any percipitate either. But, it did discolor the water.



> czado, you are saying 1.6 ml of TMG in 20 gallon tank yields 0.2 ppm Fe?


Actually, he was saying that 1.6 ml of the solution I made from Greg Watson's Iron Chelate would yeild .2 ppm Iron in 20 gallons.


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## banderbe (Nov 17, 2005)

I shouldn't post that early in the morning!


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