My own micros... How to chelate?

incubus3x3x3

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Nov 7, 2008
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Hi all. Since is my first post here I'd like to introduce myself:
I'm Andrei from Romania, and I'm 36. I'm a computer programmer and my aquarium is my primary hobby. I'm browsing this forum for a long time, but only now I found a question which have no answer here already, so now I really need you help, guys.

I'm very determined to make my own micro fertilizer hopping that it will be better and cheapper than the brand ones.
I'm still learning the knowhow from various sources and, of course, even at the step 0 I ran into problems.

It's not very hard to make the recipe itself, al least on the paper, with a little knowledge of math and chemistry but I'm stucked at the actual preparation of the iron chelates. I intend to use EDTA, DTPA and HEDTA as chelators and FeSO4 as iron salt because it is easier then FeCl3 to manipulate.

So... does anyone know what are the specifics of the chelation reaction in case of DTPA and HEDTA? (for the EDTA chelation I managed to find all the parameters).
I mean, is the proportion the same as in case of EDTA, 1:1 molar Fe:chelator?
What are the temperature and the pH recomended in the chelation reaction when using DTPA and HEDTA? Do I stir or not? ...And so on...

If anyone can give me any kind of information about this I'll be very grateful.

Tom, I understand you cannot (and for good reasons) give your own recipe of you micro fertilizer, but can you give me/us some clues? I must say that I not intend to sell the fertilizer, I only want make it for me and my friends. And I swear I will tell everyone that you helped me alot.:D (Anyway you helped me already since I read this forum from cover to cover)

Thanks,
Andrei.
 

Tom Barr

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Andrei,

I just buy it already made rather than make it. Cost less, easier, and I need a guaranteed analysis. That comes with a pre made product.

I guess you can buy it and chelator the salts yourself. I do not think you will save much money though. So........I'd search agricultural supply places for bulk sources, or see if you can find things like iron chelate already pre made in the EU.

I know they have farms there:)
So they likely have this.

They also even sell it on ebay etc.
Shipping might cost you, but likely not that much, and you only need say a 500mg amount for several years supply;)

Unless you are making a lot..........I see little reason to make a chelate metal salt from scratch like this. Even I do not bother with a metric ton of trace mix. Then I'd have to run an atomic absorption test for the % to check it.

Regards,
Tom Barr
 

incubus3x3x3

Junior Poster
Nov 7, 2008
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Europe - Romania - Constanta
Follow the elders...

Thanks a lot for your reply, Tom. I'm really, really glad that you answer me but here's a paradox. I'm also not that glad that you answer me first. As far as I could see on forums, when an elder replies, no one after him will reply anymore. :confused: I don't know why... Ok, now, as I said that, maybe no one will answer me anymore :) ... Me and my big mouth...:eek:

On-topic:
I've learned in all these years to follow the advices of the elders. So I'll try to find some pre-made Fe- in a smallest quantity possible, as small, for a bulk seller usually means at least 1Kg (2.2pounds :D )

I'm skeptic I will find what I want though, because I'd like to use at least 2 chelated products to cover a larger range of pH and none of them must contain any other micros than Fe. The agriculture fertilizers have the " habit" to contain a lot more than just chelated iron.

Hypothetically speaking, if you were me, what two iron chelates products would you choose? Assuming that you can choose between Fe-EDTA, Fe-HEDTA, Fe-DTPA and Fe-EDDHA?
(I know that there are many opinions but I’d like to know yours about stronger vs. weaker chelates, about stability of chelated molecule at different pH values etc.)

Would you also go for a "softer chelate" like ferrous gluconate as Seachem does?

Thanks again.
Andrei.
 

Tom Barr

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They sell all sorts of Fe chelated products for hydroponics growers, home health products etc, and I know they sell such things in the EU,which should not be that difficult to mail order.

You just need to search for ones that will ship to you.
Some here will I think.

I'd suspect the tap water is rather hard due to the limestone geology where you live perhaps. Most of the tap will be harder(Higher KH, and Ca, might be okay for Mg.........or not)

It's not just that I am the "elder", there's just the practical part of doing this.
I tend to not stray too far from that unless I have a really no other choice.

Regards,
Tom Barr
 

Tom Barr

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Just check, might be very easy to get everything you need with much less effort and consistent results. If you are a chemist, that's different. You might be interested then, other wise? Nah.

Regards,
Tom Barr
 

incubus3x3x3

Junior Poster
Nov 7, 2008
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Europe - Romania - Constanta
Tom Barr said:
Just check, might be very easy to get everything you need with much less effort and consistent results
Ooo, but of course I can get almost everything I need, very easy. But there are 2 situations here. The inexpensive way (JBL, Tetra, Sera), but I'm not so sure about the "consistent results" and the expensive way (Dupla, Dennerle, Seachem, ADA), which is well... expensive :)

Tom Barr said:
If you are a chemist, that's different
Well, I'm not really a chemist. Let's say I'm a half-breed :). A chemist beeing one half. So I'm still interested in trying to make that fertilizer either with chelator and FeSO4, or a Fe-chelator product already made. Of course I incline to use Fe-chelator, as you advice me, if I will manage to find the one that I would like.

I noticed that you didn't answer the question about which chelate product should you use.

Andrei said:
[...]if you were me, what iron chelate product would you choose? Assuming that you can choose between Fe-EDTA, Fe-HEDTA, Fe-DTPA and Fe-EDDHA?
Would you also go for a "softer chelate" like ferrous gluconate as Seachem does?
Is this information confidential too?:confused: I'm not asking about the one that you are using. Just asking what would you use if you were me?
Or, let me put it another way: Is Fe-DTPA good enough? Isn't it too strong so even the plants can't get the Fe out of it?


Thanks.
Andrei.
 

Tom Barr

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Jan 23, 2005
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I did not answer your direct queston because the hassle of making and trying to ensure consistent results is tough, few aquarists can even measure Fe in solution correctly, let alone quanatify the % chelated and % unchelated. Chemist have done their entire PhD's on chelation. What about the old chelators such as ETDA? Does it go back into the bound forms as Fe breaks in and out of the chelation? The alklainity really determines a lot there also. You have a dozen things occuring. It is not some simple answer. I'd just use Sera personally since it's cheap.
DTPA is fine, the Tropica label uses it.

It works, but KH determines what's best where you get the most out of the chelator. We add excess traces anyway and perhaps a fair amount gets wasted, but it's really hard to make certain that it's all used up.

Look, you are a chemist or something close, you should be able to look things up here and make your own. I do not bother personally. It's not worth my time. I just buy what I need and that's the end of it. I look up the KH etc for my tap etc. Fe is much less to do with it because there's another 6 other traces I am using and dealing with in %.

I'm not going to make all that from scratch. How to chelate articles in chem text books are available, I'd look there.

Having used Sera in the past, I found it pretty good results wise for plants at a KH oif 5.5.

Regards,
Tom Barr