Edta Versus Dtpa

Steven Pituch

New Member
Dec 30, 2020
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Hallettsville, TX
Hi all,
I have been dosing EI for a month. Liquid with traces and macros in separate bottles. The traces are pure Plantex CSM+B with 6.5% Fe, 65.4% EDTA. My new growth in my narrow leaf swords and micro swords is yellow. I tried overdosing K, P, and N separately (also to the roots in capsules) but the deficiency persisted. My KH is 14*and I try to keep the PH down to 7.2, 7.3 with CO2.

So I read that EDTA is not effective above PH = 7.0. So I purchased some DTPA/(11% Fe). DTPA is not effective above PH = 8.0, so I figured at 7.2-7.3 I should be making some Fe available to the plants. I added a pinch of DTPA/Fe to the water column in my three tanks. Two days later all the new yellow growth has turned a bright rich green. I think I have solved my first plant deficiency. I would think this knowledge would be generally known. It seems if you have hard water, you need to use DTPA/Fe.

So can I add the DTPAFe to my CSM+B trace solution? I’m afraid of the EDTA affecting the Fe.

I’ve seen trace elements for sale with both EDTA and DTPA.

Sincerely,
Steve Pituch
 
Last edited:

Steven Pituch

New Member
Dec 30, 2020
9
4
3
69
Hallettsville, TX
This is from one of the EDTA/DTPA/PH articles:

“ EDTA strongly holds iron in solution up to pH 6.0, but by pH 6.5, almost one-half the iron is precipitated, and by pH 7.0, almost none of the iron is available to plants. DTPA is an excellent iron source up to media pH 7.0; however, 60 percent of the iron is precipitated and unavailable by pH 8.0.”

Here is the link: https://www.canr.msu.edu/news/selecting_which_iron_chelate_to_use

Regards,
Steve P
 

Steven Pituch

New Member
Dec 30, 2020
9
4
3
69
Hallettsville, TX
Based on the literature referenced by Pauld738, it seems to imply the DPTA/Fe and the EDTA/Fe will not influence each other. I guess the iron is actually bonded to the DTPA.

When I mix trace elements again in 500 ml of water, I will add enough DTPA/Fe to make .1 ppm Fe in my tanks. We’ll see how that works.
Steve
 
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