# Iron EDTA or DTPA or both?



## audioaficionado (Apr 19, 2011)

I see them both for sale. Is one better than the other? 
Would a mixture of both be even better?
Are there other chelators I should consider?


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## dafil (Jul 17, 2010)

What is your ph?
If you have around 6,5 -use EDTA
If you have 6,5-7,5-use DTPA
other chelators like EDDHMA,EDDHA are stable even at ph 9-10.
But they will colour your water for a while.


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## audioaficionado (Apr 19, 2011)

Thanx. I used EDTA in electroless copper plating baths when I was still working in the printed circuit board manufacturing industry years ago.


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## happi (Dec 18, 2009)

EDTA in lower KH, PH is not important IMO. DTPA if the water have high KH. you could still dose EDTA in high PH/KH but you might have to dose 3x more than recommended dose.


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## audioaficionado (Apr 19, 2011)

What's considered high/low KH?


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## happi (Dec 18, 2009)

audioaficionado said:


> What's considered high/low KH?


am not sure if you are trying to make fun of my previous post but here is the answer anyway, High Kh effects the way plant absorb the nutrients and co2 etc, Kh of 6 is considered good for most plants, having higher Kh mean more co2 and more ferts needed by plants, still they will have hard time using those nutrients. 

my tap water is Ph of 7.0 and kh of 6, plants still struggle if i don't dose extra stuff.


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## DerangedCorgi (Oct 15, 2010)

I don't think he's making fun of you... c_c I'm wondering the same thing too, what is actually considered high and what is low. 

e.g. <=4 is considered low and >4 is considered high, etc.


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## audioaficionado (Apr 19, 2011)

^^ Correct.

Once I get a Python or equivalent water changer, I'll be going into full EI mode w/GH booster. I can get either EDTA or DTPA or a combination of both to boost my iron to Tropica micros levels. My pH is generally ~6.5 or less with my DIY CO2 levels at lime green. I'd like there to be enough calcium to help the snails and shrimp not to dissolve over time.


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## happi (Dec 18, 2009)

audioaficionado said:


> ^^ Correct.
> 
> Once I get a Python or equivalent water changer, I'll be going into full EI mode w/GH booster. I can get either EDTA or DTPA or a combination of both to boost my iron to Tropica micros levels. My pH is generally ~6.5 or less with my DIY CO2 levels at lime green. I'd like there to be enough calcium to help the snails and shrimp not to dissolve over time.


just making sure , anyway having a PH of 6.5 with the co2 mean that you have PH of 7.2 or something without co2. you should test for KH if possible, everything else about the water is no need to worry. if your water read high TDS, then you might have Ca and Mg or just Ca and no Mg, if plants don't do well add Mg. 

if you want you can try both EDTA or DTPA and see the results for yourself.


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## dafil (Jul 17, 2010)

Google translate
http://translate.google.bg/translat...nia.110mb.com/Chapters/Tech/liqfert-main.html


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## plantbrain (Dec 15, 2003)

You can simply use both and add about 1:4 ratio of DTPA to CMS mix.

Covers both bases that way.


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## audioaficionado (Apr 19, 2011)

I'm going to make up DIY Tropica Plant Nutrition.
DIY Tropica Plant Nutrition! Mix your own Micro solution on the cheap!
I want to get enough of everything and not too much of anything.
Seems that CSM+B & Miller's MicroPlex each have things the other doesn't.


Green Leaf Aquariums said:


> Plantex CSM Miller's Microplex
> --------------------------------------
> Fe 7.0 % 4.0%
> Mn 2.0 % 4.0 %
> ...


CSM+B has boron too.


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## ray-the-pilot (Jul 5, 2011)

audioaficionado said:


> I see them both for sale. Is one better than the other?
> Would a mixture of both be even better?
> Are there other chelators I should consider?


It doesn't really matter since 99% of the iron will be in your filter or substate in 24 hours. Soluble iron dosing is a one shot thing. You should dose iron every day.


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## audioaficionado (Apr 19, 2011)

ray-the-pilot said:


> It doesn't really matter since 99% of the iron will be in your filter or substate in 24 hours. Soluble iron dosing is a one shot thing. You should dose iron every day.


That may be true for straight ferrous sulfate oxidizing to the less soluble ferric ion, but chelators are able to hold the metal in solution much longer as a complex rather than a simple dissolved salt.


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## ray-the-pilot (Jul 5, 2011)

audioaficionado said:


> That may be true for straight ferrous sulfate oxidizing to the less soluble ferric ion, but chelators are able to hold the metal in solution much longer as a complex rather than a simple dissolved salt.


 Really? I tried testing for souble chelated iron and couldn't find any after 24 hours. If you have a favorite formula, I'll see if I can find any in solution after 24 hours. (The next question is: With iron that is so stongly chelated, can any plant use it?). 
I take iron supliments every day and dose iron every day. The thing with plants is many can get iron from the substrate.


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## plantbrain (Dec 15, 2003)

ray-the-pilot said:


> It doesn't really matter since 99% of the iron will be in your filter or substate in 24 hours. Soluble iron dosing is a one shot thing. You should dose iron every day.


This is not true.

DTPA will exist for about 2-3 days for a KH of 4. 
ETDA a few hours.


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## plantbrain (Dec 15, 2003)

ray-the-pilot said:


> Really? I tried testing for souble chelated iron and couldn't find any after 24 hours. If you have a favorite formula, I'll see if I can find any in solution after 24 hours. (The next question is: With iron that is so stongly chelated, can any plant use it?).
> I take iron supliments every day and dose iron every day. The thing with plants is many can get iron from the substrate.


Which type and what is the alk of the water?
Also, can you assume that it was not simply removed by the plants?

Regarding the chelator, yes, plants can take the Fe out of the chelator, strong bond energy requires more energy from the plant, but relative to the overall energy, budget, this is a very minor issue. The main issue is the Fe in solution and/or in the sediment pore water and not precipitated.

Bond energy has little effect.

In otherwords, we could use DTPA in place of ETDA, but ETDA is cheapest and widely available, but I do not think anyone would see any difference between them growing aquatic weeds.

We can add little spike of DTPA to CMS and it's pretty much like Tropica.
Claus Christersan who use to work for Tropica developed it and said the same things I am. This way the product can work well in soft, moderate and harder waters. Plants can use the easy stuff and then take up anything that's left later. 

Dose = exposure x concentation

So the longer it's available, the better for exposure......but the trade off is a little bit more energy for that. Not every doses daily also and not every one is going to do that.


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## audioaficionado (Apr 19, 2011)

plantbrain said:


> This is not true.
> 
> DTPA will exist for about 2-3 days for a KH of 4.
> ETDA a few hours.





plantbrain said:


> You can simply use both and add about 1:4 ratio of DTPA to CMS mix.
> 
> Covers both bases that way.





plantbrain said:


> ...We can add little spike of DTPA to CMS and it's pretty much like Tropica.
> Claus Christersan who use to work for Tropica developed it and said the same things I am. This way the product can work well in soft, moderate and harder waters. Plants can use the easy stuff and then take up anything that's left later.
> 
> Dose = exposure x concentation
> ...


I believe I have my answer.
Thanx Tom.


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## ray-the-pilot (Jul 5, 2011)

plantbrain said:


> This is not true.
> 
> DTPA will exist for about 2-3 days for a KH of 4.
> ETDA a few hours.


Im not sure what you mean by this statement?
Do you mean that DTPA can be found in solution after 3 days or Fe can be found in solution after three days

While I cannot argue with either statement since it is not quantitative. I do not doubt that some Fe is in solution forever so to say that it lasts 3 days is obviously correct.

My experience testing for Fe using a test that can measure to about .01 PPM Fe is that if I start with a original tank level of .1 PPM Fe after 24 hours, I cannot find any Fe using my test. This is a fact.

I can find lots of Fe in my filter and substate; so my guess is that most of it winds up there. 

My KH is 4.0 and I use a UV filter so this may affect the half life of the EDTA/DTPA complex. In either case they don't last long.

Please note that when I originally posted this I was off by a factor of 10 in my test specs. The corrected specs are above. (Must be getting old?)


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## 150EH (Dec 6, 2004)

I'm going to use Iron Chelate 11% DPTA, so would it be better to dose in the morning while the pH is higher. My water parameters are pH 7.4 out of the tap but for some reason 7.2 in the tank and will drop to 6.8 or so with CO2, and the kH is 6.9

So I need laymen's terms, what I got out of this is: it would be benefitial to dose early in the day and at the higher end of reccomended amounts.

I know the threads is old but I'm hoping someone will give me the answer.


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