Chelated Iron Dosing - Is there such a thing as a preventive dosing?

[Roger Pilon]

Is there a specific dosing of chelated iron that one can add to his system as a preventive dosing!

I know that when you see yellow leaf appearing it is normally time to add chelated iron. This said, I would like to know if there a specific dose that you can add weekly, monthly to keep your AP system in a happy iron level?

Not too much, not too high... just enough to avoid a lack of iron!

Some specs:

1. I have a chelated iron EDDHSA 6% (Fe)
2. Using a IBC tote with 1000 liters water +/-
3. 2 x (4x8x12inches) Deep Floating Raft 
4. PH is at 6.8 / 7 range

Any advices would be welcome!

Roger Pilon

Costa Rica

[mary proctor]

You are so right on the PH.  We had yellowing of leaves  the 6 beds on one side of the aquaponic house and perfect green on the other side with 6 beds.  We were stumped on why that was.   We put sprayed chelated iron on our yellow leafed plants and it helped out somewhat....then we noticed that we had NOT PUT A PIECE OF DRIFTWOOD in the fish tanks on the side that had the beds of yellowing  leaves.  We had found out thru the enternet blogs on natural  driftwood pieces from the lake or streams/river takes the PH down. We also found out that sorgum moss put in old nylon hose and/or net attached to the return water to flow over  from your beds would also bring down the PH.  We have not tried this moss ... since the driftwood did the trick.  Sure hope this helps you out.   Mary

Jon Parr said:

Ok. I should not have said "cannot" overdose. Please strike that statement from the record. I can say that iron overdose is rare, and generally not harmful to fish and plants. I found some accounts of 20-40 times the recommended dose with no ill effects, and likely the only result is a reduced availability of P. Also, iron deficiencies may be the result of high pH, not a shortage of iron. Maybe Nate will chime in, he knows his iron.

[Shas Cho]

Here's my question regarding chelated iron:

If it is purchased from a garden or hydroponics store
it will likely be chelated with DTPA (Diethylenetriaminepentaacetate).
The makers of iron dietary supplements from the health food shop
seems to be a bit reluctant to list the actual chelating agent,
saying things like "amino acids"
(is DTPA not an amino acid?).

I'm wondering whether horticultural and human supplements
are actually the same thing
(gee, I can buy dietary supplements at Walmart garden centres!).
If they are not, how safe are the plant supplements for fish?
And for people who eat those fish?

Does anyone have firm information about this?
(guesses I can come up with myself!)

Maybe blood meal is the safest form of iron for aquaponics?

[Vlad Jovanovic]

Fe-EDDHA and Fe-HEDTAare also common (at least here). I don't think that DTPA is used in dietary supplements? Though there are some MRI contrasting agents (directly injected into a persons bloodstream) that use DTPA and/or their derivatives as the 'major ingredient', so I'm guessing that it would be safe in a horticultural/food production context. Sorry if this is not much help.

Stay away from EDTA (if it is even sold anymore, as it is a proven toxin. Plants at least, people too if injected.

Blood meal will also add lots of N.

Anoxic conversion of ferric iron (Fe3+, like rusty nails) to plant usable ferrous iron (Fe2+) may be the safest form of iron for an AP system if the chelates freak you out.

[Shas Cho]

Vlad Jovanovic said:

... there are some MRI contrasting agents... that use DTPA and/or their derivatives as the 'major ingredient', so I'm guessing that it would be safe in a horticultural/food production context.

You're a trusting soul, Vlad.

Those imaging techniques use lots of things

that you wouldn't want to ingest on a regular basis,

and I'm guessing that DTPA is one of them.

Also, excessive chelating agents can strip the body

of various minerals and compounds that we need.

Which sort of brings me back to the question

of whether horticultural potions are appropriate for use in aquaponics...

"Blood meal will also add lots of N."

True. 

I would expect a well-planted grow bed

to take up the nitrogen fairly quickly, though.

Lots to learn in this infant science.

That's part of the charm of it, to me.

[Vlad Jovanovic]

Hehe...Thank you Shas, I've been called many things in my lifetime, but 'trusting soul' is a first. Paranoid bastard, or some derivative thereof, is more along the lines of what I'm used to. So thanks...

You are right, you certainly would not want to ingest those things in any quantities on a regular basis. DTPA and other chelating agents certainly can strip the body of various minerals. It is exactly because of their ability to do that, that they are used in certain medical procedures/therapy. You normally would not want such a thing...Weather the amount used in hydro or AP is acceptable over time...? That's probably all really just guesswork at this point?

So again, if the idea of makes someone wary, there are always alternatives...Blood meal may be one? This may be another...Nitrogen cycle is just one of a number that we humans can set up and steward. Iron cycle too can be used advantageously as well if done properly and in the correct setting...

Conversations with a Really Smart Guy (RSG)

http://aquaponicscommunity.com/forum/topics/organic-or-otherwise-ho...

[TCLynx]

I'm confused Vlad, I thought on the previous page you said the DTPA was the one toxic to plants and now you seem to be saying the EDTA is the toxic one??????

[Vlad Jovanovic]

Holy cow! Your confusion is well warranted! EDTA is the known toxic one. DTPA is the recommended chelate, even though EDTA is still listed in a lot of formulations. 

Big time typo on my part..Again,

DTPA = "good"

ETDA = toxic

Man, I should really read my own posts before I post them. Thanks for catching that TC :)

[TCLynx]

Help this poor chemistry challenged and dyslexic technician here.

What does DTPA stand for spelled out?

What does ETDA stand for spelled out?

See many of the products don't list the initials but the actual words spelled out and I don't know how to translate.

[Vlad Jovanovic]

DTPA is Diethylenetriaminepentaacetic acid

EDTA is Ethylenediaminetetraacetic acid

EDDHA is ethylenediamine-di(o-hydroxyphenylacetiz) acid

Well at least they all have very safe sounding, easy to pronounce and 'comforting' names :)

[Roger Pilon]

You can add this to the request: EDDHSA!

Roger

TCLynx said:

Help this poor chemistry challenged and dyslexic technician here.

What does DTPA stand for spelled out?

What does ETDA stand for spelled out?

See many of the products don't list the initials but the actual words spelled out and I don't know how to translate.

[TCLynx]

Thank you

[Vlad Jovanovic]

ooh thats the best name of 'em all...

EDDHSA is ethylenediaminedi(2-hydroxy-5- sulfophenylacetic) acid :)

Roger Pilon said:

You can add this to the request: EDDHSA!

Roger

TCLynx said:

Help this poor chemistry challenged and dyslexic technician here.

What does DTPA stand for spelled out?

What does ETDA stand for spelled out?

See many of the products don't list the initials but the actual words spelled out and I don't know how to translate.