How long iron gluconate "live" in tank

Wow... I had thought gluconate was kind of short lived but I hadn't realized that it was this brief.

I can see the possible advantage of spiking something easily available and short lived though; aquasoil's NH4 does things for plants that are incomparable with NO3 once the substrate cycles. It'll be a nice pairing with CSM+B's EDTA for aquasoil/low pH tanks.

I take it EDDHA is some pretty tough stuff for plants to break down? The price doesn't seem much off other chelates.

 

Plants can get the iron from the chelate directly, they don't need iron to be separated. The fact it resists to PH doesn't mean plants will have a tougher time to get it. In calcareous soils, EDDHA showed to be a very good iron supplier, so plants don't seem to bother

Gluconate could be a good alternative for a low maintenance tank with few WC. Gluconate is rapidely bioavailable while other chelates will take tens of years to degrade. Accumulation of chelates in soil can decrease its fertility. Also, I'm not sure if fish likes it in the long run at high concentrations.

Many unknown questions. If you use 50% WC, DTPA or even EDTA can be enough. Otherwise, DTPA is a good alternative, EDDHA for really calcareous conditions and gluconate as the "Bio" way!

 

Okay, so the whole thing is more of a shotgun approach for the usual issue of serious research funding. I understand completely.

What I need to work on then is my understanding of how chelates interact with nutrients and uptake.

Thanks for the clarification, both of you.

 

Thank you Tom for these clarifications. I never thought that biodegradation of DTPA was that fast. One thing the paper doesn't adress is the accumulation of DTPA in the sediment, where light can't diffuse. Their graph shows well that DTPA will last for years in the dark. What I know is that DTPA can be pointed as one cause of soil infertility if too much used/accumulated. And, seeing their graph, it seems that DTPA will for sure accumulate in soil. Add to this, the paper is sponsored by Dissolvine ad-ons, so a chelate producer...

Now, if based on your expierience, the use of DTPA in non CO2 tanks with so low WC is safe for 1-2 years at least, then I'm fine.

 

I fully agree with this

A last question: if when dosing Fe in tank you have a good reading, does this imply necessarely that enough Fe is available and no need for further dosing?

 

Maybe I was not clear:

I begun dosing CSM+B alone. Now, my Fe is 1ppm. Does this mean I have 1ppm iron available to my plants or it can be as other unavailable forms.

By the way, this is to compare to my previous dosing with TPN where I always kept 0.1-0.2 ppm without issues

So, when my tank shows 1ppm, can I just stop dosing micro or should I continue (I only do a 50% WC every 3 weeks now)

 

So,

Anyone can help saying if dosed Fe in water with test kits is the Fe potentially available to plants or can be other kinds of unavailable Fe despite a good dosage with test kit?

 

LaMotte Fe Test

The simple iron test kits may not detect chelated iron.
I wrote to LaMotte inquiring about a test for aquaous Fe(II) plus Fe-EDTA, low range, indicating that I
would be happy with the total amount. I also inquired if their tests detect Fe-EDTA.

Here is the reply that i received from Richard LaMotte

"we checked with several staff here and could not find a suitable option for you in our product line"​

I suspect that the tests for Fe(II) will detect Fe gluconate, and if allowed to stand long enough may also see FeEDTA (due to photosensitiviy). LaMotte's reply suggests that there's may not be reliable or able to detect stronger chelators.

 

"So, when my tank shows 1ppm, can I just stop dosing micro or should I continue (I only do a 50% WC every 3 weeks now)"

I may misunderstand this question, jonny_ftm, but for clarity it is important to note that Fe levels in traces are only a proxy for all trace levels. So, let's say your tank uptake Mn from CSM+B -- having Fe available does not mean Mn is available. This is where the regular input crowd will yell "See!"

I like Tom's points about using different chelators of varying strengths as a sort of staggered approach. I will be trying this in a couple weeks (other experiments with EDDHA at a hobbyist level first) but believe barbarossa4122 is now.

I'm sorry I do not check multiple forums and especially this one in some time. Time forces me to be mostly monogamous with aquatic forums. But for those not on APC, here's some things about EDDHA as Sprint 138 copied over:

What we know about EDDHA chelated Fe (Sprint 138, aka "Super Iron")

6.0% EDDHA Chelated Fe. The label looks like this:



Default
What we know about EDDHA chelated Fe (Sprint 138, aka "Super Iron")

6.0% EDDHA Chelated Fe. The label looks like this:
This image has been resized. Click this bar to view the full image. The original image is sized 800x600.


It is a very dark substance that will stain the water. The left is a large (~1.0ppm into 20 gallons) wet dose and the right the trial/experiment sample of dry. I am sorry for the cellphone pics. I'll update these images this weekend if you'd like.


Weight trials (10) for 1 leveled teaspoon (5mL) show a density of 2.42 grams per 5mL.

Trials (scale accurate to 10mg)
2.42g
2.42g
2.43g
2.42g
2.42g
2.42g
2.42g
2.42g
2.43g
2.42g

So,

about 1/8tsp adds 0.2ppm Fe into 25 gallons.
about 1/16tsp adds 0.1ppm Fe into 25 gallons.

Here is a calculator I built that does Plantex CSM+B, Miller, 10% DTPA and 6% EDDHA Fe
http://wet.biggiantnerds.com/fe_calc.pl

At 0.2ppm Fe it will color the water pink. Certainly gets your plants redder looking ... an optimist might call it a free 9325K effect This video is currently being processed by YouTube but has a test of 0.2 ppm Fe into my tank. It still retained a pink tint ~12 hours later.
http://go.aquaticplantcentral.com/?id=673X1261&url=http%3A%2F%2Fwww.youtube.com%2Fwatch%3Fv%3DZCTu8ClcMKc

I am going to continue to experiment with this chelator. However, the side effects probably mean we have to use it at a low concentration, which may mean it can only be a supplement to other sources of Iron. For example, Tropica uses some percentage of DTPA and HEEDTA in their solutions, and Tropica Master Grow is a pinkish purple that does not noticeably tint the water column after 5 minutes of dosing. I can continue updating in this thread if there is interest else I'm sure I'll post about it in whatever threads it is relevant in

... and here's 0.02ppm dosed into my tank (forgive the mess) and 10mg into a cup with exact light (nfrank's request for a photosensitivity test):


and the same 3 days later: