How long iron gluconate "live" in tank

[Tom Barr]

EDDHA is only used in small amounts and typically for only folks with those higher KH's, say 8 or more.
That seems about correct, I'd still only use say 0.1ppm per typical dose of that type of Fe.

So with harder KH's,. I'd still use liberal amounts of DTPA+ EDDHA, not much.

Otherwise, stick with DTPA.

The only REAL method to test Fe with chelation is really to do 2 things with plants.
Know what you have dosed to the water, say you added 4ppm of Fe as 45% Fe DTPA, 50% ETDA, and 5% EDDHA.
Next measure what the dry tissue Fe content is.

I suppose you could also do growth rates, and measure the total dry weight biomass for each chelation type or blend and compare those. 6 ppm gave the highest rate of growth for Hydrilla, 8ppm gave the highest rate of uptake/ % Fe in tissue of the plant using ETDA Fe in one of the few applied studies on a submersed aquatic weed.

Quite a bit more than what typically is dosed by a hobbyist.

As I have the same product, I do not think there's going to be much difference in the weight of the Sequestrene 138.

Regards,
Tom Barr

 

[bsmith782]

What is the chelator for the Fe in CSM+B, DTPA? And is there an acronym for the gluconate in Flourish Fe or is it just plain old gluconate?

 

[Wet]

My favorite Poaceae farmer!

CSM+B uses EDTA as its chelator. The stuff in Flourish is just known as ferrous (Fe) gluconate.

 

[jonny_ftm]

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?

No

Regards,
Tom Barr

Sorry Tom to insist, but, could you explain more? What kind of Fe is shown then in those kits? If they can't detect some sorts of Fe, at worst they under-estimate the Fe in water. So why, when a test kit shows 2 or 3ppm of Fe could it be that no Fe is available to plants? I really have a hard time to get it?

 

[Tom Barr]

This is an old question(see APD pre 2000), I've long stated not to bother using any Fe test kits to measure water residual concentrations in aquatic plant tanks, there's no correlation.
Do not waste your time testing Fe.
There's a number of reasons for this both inorganic/organically-biologically.

If your solution does have 2-3ppm of Fe, this assumes the test kit is correct and is measuring the correct type of Fe/chelation etc.
I'm not sure test kits are able to do this.

I also can never measure any residual and have plants do very well.
Can they do better if there's a residual always present? I'm not sure.

I think it's best to use the plants to answer this question.

Dose more and more until you have no net gain in aesthetics or growth, then step back to the next lower dosing.
You'll be surprised how much trace mix you might add.

Folks have long been scared of Traces like they have of PO4.
Cost is a big concern with name brands, but if you have 5 lbs of CMS+B, 1-2 lbs each to DTPA, gluconate and EDDHA, it's very cheap.

So then there's little reason not to explore the upper bounds.



Regards,
Tom Barr

 

[jonny_ftm]

If your solution does have 2-3ppm of Fe, this assumes the test kit is correct and is measuring the correct type of Fe/chelation etc.
I'm not sure test kits are able to do this.

I also can never measure any residual and have plants do very well.
Can they do better if there's a residual always present? I'm not sure.

The JBL test kit can detect as low as 0.05ppm Fe, and it really does when calibrated against solutions of either TPN or CSM+B, that's a fact.
My plants were doing as I liked dosing only 20ml TPN/week in my 60gal (40gal water). That's just 0.1ppm Fe added /week, really anecdotical. As I do one WC/3weeks, my residual Fe before WC was between 0.1-0.2ppm.
I moved for costs to CSM+B (not having yet any DTPA) with a dosing of about 0.8ppm/week Fe, WC every 3 weeks only. The test kit max range is 2ppm and it shows a residual level of around 1ppm. Plants are doing just as before, they look very healthy, fish is fine, no algae...

As EDTA is said to be a weak chelator in high PH, I wanted to know if the Fe actually in water column is available to plants or not. That is, any Fe detected by the kit, is soluble Fe and thus available?

In any case, I see your point of view very well: why bother when you know that dosing is safe. I agree fully, but just like to know better what I do, and especially, for the long term health of live stocks, I hate dosing above what is needed. Since my tanks don't have algae (thanks to EI, even if customized for my needs/tanks/ights), I still prefer the way of less dosing while still dosing above plants needs. But in my mind, 0.1ppm in TPN giving same results as 1ppm in CSM+B is hard to accept.

 

[bsmith782]

To Czado

I knew it was you, you giant nerd!

To J FTM,

I posted in another forum that I had less than stellar actually pretty crappy results with just CSM+B in my 'high tech' tank. My plants looked like they were starving for something. Since I dose EI for my size tank I knew that the Macros were more than adequite. After I could no longer take the state of my tank I caved and got a 250ml bottle of Flourish Fe to get me by and in 2 days my tank looke like it was on its way back to it's beautiful glory. What I mean by that is that all of the groth post re introducing Flourish Fe lookes succulent, vibrant and gorgeous! After about a week I fecieved my Flourish Comp and started dosing that again aswell. So in my application (high tap PH but being buffered by the ADA AS Ammazonia substrate) the instand availability of gluconate made all of the difference.

 

[jonny_ftm]

Hi bsmith782,

Thank you for your feedback on Gluconate Fe, but that only shows that each tank is different, it just doesn't answer my question: if a calibrated test kit measures 1ppm of Fe, is all the measured Fe soluble and potentially available to plants or part of it could be unavailable: that is chlorosis despite the high Fe detected in water?

 

[bsmith782]

Hi bsmith782,

Thank you for your feedback on Gluconate Fe, but that only shows that each tank is different, it just doesn't answer my question: if a calibrated test kit measures 1ppm of Fe, is all the measured Fe soluble and potentially available to plants or part of it could be unavailable: that is chlorosis despite the high Fe detected in water?

Not too sure on that one, I just let my plants tell me what to dose.

 

[Tom Barr]

Hi bsmith782,

Thank you for your feedback on Gluconate Fe, but that only shows that each tank is different, it just doesn't answer my question: if a calibrated test kit measures 1ppm of Fe, is all the measured Fe soluble and potentially available to plants or part of it could be unavailable: that is chlorosis despite the high Fe detected in water?

No.

I would also say that if you dosed say 1 ppm of ETDA to a planted tank, adding it, (not testing the residual in the water) then yes, there's ample Fe for that point in time.
However, in 1 day, the residual will have moved a considerable amount.

When you measure the Fe is critical. Test kits are not all they are calimed ot be when it come to measuring Fe for plants in solution due to various chelators etc.

See Neil's comments.

I think even unavailable Fe in solution is still somewhat avail;able, but it's more an efficacy issue here.
DTPA will take less ppms than say Gluconate to yield the same result. Weaker the chelations/ligand, the more wasteful it might become, but the easier it is for the plant.

That is the trade off with the different forms and formulations of trace mixes/Fe chelation.

I do not think aquarist will have any clear cut evidence either way, so rather than trying to go down that path, I hedge my bets and cover all the bases using the theory for pH optima for different chelators with multiple forms of Fe chelators.
that way no matter what preferences plantds have, or what pH/KH the aquariums have, or the denisty and type of plants, I have always ensured there's the leats chance for limitations to occur, much like EI. Excess related issues seems rare, I've dose some really high levels, but only a very few pulses and then wait for a few days.

I think there's no issue at 1ppm ranges, I do not think many will get that much difference beyond that range though(based on dosing to a know volume of aquarium water with a known stock solution of Fe etc, not using a test kit to measure the water itself).

Regards,
Tom Barr

 

[jonny_ftm]

Thank you Tom for your answer,

I understand better now even if still some foggy parts remain: what's going on whith the Fe detected by my kit and how does plants can't use it?
I'll try to research it in soil based tests/data.

The difficulty is that I'm moving to a less WC EI based routine: so 50-70% WC every 4 weeks. Now I'm at one WC/3weeks and plants do very good. Managing the P and N accumulation with th efewer WC is easy. However, with a WC every 4 weeks, I fear the accumulation of micros in CSM+B, that's why I'm looking for a way to monitor how much I could go up/down on micros. Observing the plants is the best way, but hoped to make it quicker by targetting a residual Fe in water

 

[Tom Barr]

I do not think there's any risk associated with trace build up, I've never seen it in any tanks so far.
The non CO2 dosing is less, about 6-10X so, but there's no water changes for years in many cases.

Plant biomass takes up a lot of the metals, even if they are non limiting for growth, so there's export in that form.
I do not think you need to worry at all about P management, even over a 4 week time frame, just make sure there's in excess of say 2ppm.
NO3 management as well, do not let it fall too low, and the upper range is also quite high, but most can target 30ppm to 10ppm with Lamotte test after a few months and then there after, can by pass testing altogether/entirely.

I do not think that is hard at all to do. If the plants have trouble, many have too much light to make the balance easy, so less light helps reduce plant issues.
As long as you do not run out, go too low, I think most do well with reduced water changes.

Some testing is still useful, but folks can also use the plant test approach, watching them and adjusting down slowly etc, and progressively, till they see a negative sign, then adjust back up to the next higher level.
But, you can also use just a good NO3 test kit and make a set of reference standards, say 5-10-20ppm to check the test kit and your eyes against the color chart they provide.

The excess range for PO4 is extreme, I'd say the trace issue is as well.
If you prefer this type of routine, I also would strongly suggest ADA aqua soil or a DIY version so there's ample back up in case you forget to test or dose. Things happen. Best to plan for such error.

This way if you go lean in the EI dosing, you have a back up.
Sediment ferts are certainly a good option for long term reduced water change methods.

Non CO2 water column dosing methods work well also.
Surly there are hybrid methods that use a little of both sediment+low light+ reduced water column dosing + monthly water changes.

Your error range goes up, and this can be managed with NO3 test kit(Fe has not really been an issue near as anyone can tell, and PO4 has no known upper bound anyone can find other than salt stress and the same is true for K+ etc), or predicted better using a back up like sediment nutrient sources/less light etc.

Regards,
Tom Barr

 

[jonny_ftm]

Thank you Tom for the hints,

I'll keep dosing micros then, and try to decrease by 2x if aquarium does well with WC/1-2 months. I no longer test PO4 indeed as most test kits are not accurate above 1ppm, so usefull only when we try to low-dose, which, as you say, is useless with PO4.

I use NO3 and conductivity to monitor my dosing, waste management and waterchange. I'm noticing that with a waterchange every 3 weeks, I still need about 15ppm NO3 dosed/week. Seems lean but makes my NO3 stay between 10-25ppm with a Salifert calibrated test kit. Once twaeked, I won't test anymore of course. And even now, I test every 1 or 2 weeks

I'm just worried about fish as a 50-70% WC every 1-2 months could result in a greater difference between tank water and change water, thus a stress and long term diseases with fish. So I go slowly

 

[barbarossa4122]

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./QUOTE]

Yep, I am dosing this for the last 7 or 8 days and everything it's OK, so far.

1L of DI water
2 TBS of CSM+B
2 tsp of DTPA Chelated Iron
1 tsp of Sprint 138-"Super-iron," Sprint Fe 138 (6% Fe-EDDHA)
20ml of Excel (for mold and fungus)

Also TPN 3*/week and some Flourish Iron from time to time.

 

[Wet]

As usual, Left C was helping a subscriber with awesome advice and information when he mentioned this. I thought I'd give it a try.

The various forms of Fe, different chelators, suggestions on the amount to dose, etc has me confused.

The below is debatable but I think most would see the justification for this ball park chart:

pH/KH           EDTA           DTPA           HEEDTA		EDDHA           Gluconate

Low		 *		*              *                                 *

Moderate	                *              *                 *               *

High				*              *                 *

We have to care about photosensitivity, too, and probably lots of other stuff. Generally speaking DTPA is the best stuff to use if you'd like to try dosing isolated iron because a) it keeps Iron in its proper state for a good amount of time and b) it is inexpensive and readily available online.

Folks who have found gains from isolating iron become curious about frequency and levels of dosing and playing with different forms of Fe. Just like any nutrient there are wide ball parks, but figuring 0.1-0.2ppm Fe in addition to whatever Fe you're adding from your comprehensive trace mix is a good place to start.

Much of the thought with these recent discussions, at least from my perspective, is how guys like N. Frank can dose traces once a week and show plus plants. Now, his tank has slower growth than mine and he is more reasonable about light. He also has much softer water than I do. But he also uses Tropica Plant Nutrition, which happens to use EDTA and HEEDTA forms of iron. Now, my schedule uses EDTA chelated and DTPA chelated Fe and it works great but, you know, I'm up for trying something new. And so now I'm wondering if I can get away with once a week dosing, too, by using different forms of iron.

Tom likes the idea of mixing them all together in a proportion that keeps no downsides (certain chelators tendency to color the water, the amount of time they stay in solution, etc). I think everyone in this thread shares this same instinct.

Keep in mind that some Fe that becomes unusable (oxidized) eventually becomes usable again after reaching anaeorbic conditions in our substrate. Discussion here is strictly with input into the water column but Tom and Walstad and others have discussed Fe as a whole in our aquariums.

I hope this helps.

 

[CL_]

Inspiring and doable in the water column with enough small tanks (cups?) with matching top off schedules, no? Non-limiting and DI as extremes is a good idea. It's still always eye opening to see "Relative Growth Rates" when using the former vs anything else, even after all these non-limiting benchmarks with various nutrients you've posted over the years. If using solution instead of soil, am I silly to think it easier to let the plants dry up for a day then weigh instead of the paper towel thing, which I think most of us won't have the same enthusiasm for through all samples?

Tricky though is your Fe example for those of us who concur with your findings on "sheen" (I would go as far as leaf density and overall plant health and color, not necessarily red) without the cost for chemical analysis Maybe we could grind up the plant mass and titrate the Fe out

Ahh, that would be a fun experiment to do in AP Chem. class. Now that I think about it, we haven't done a lab in a few weeks. Too bad we don't cover much biology in that class, if any at all.

 

[Wet]

Ah, to have access to a nice lab again. If you can do this or make a test to measure Fe (or, say N or P) in plant tissue the rest of us can do with affordable stuff from some classroom or science supply, I'll send you some DTPA and EDDHA chelated Fe for your science project or extra credit assignment or your desire to help all of us or whatever.

 

[CL_]

Ah, to have access to a nice lab again. If you can do this or make a test to measure Fe (or, say N or P) in plant tissue the rest of us can do with affordable stuff from some classroom or science supply, I'll send you some DTPA and EDDHA chelated Fe for your science project or extra credit assignment or your desire to help all of us or whatever.

I have done titration before, and I know that one of the lab rooms has a plant growing light (though, it might be in use ATM)
Basically would the tests involve growing a few samples of a certain plant(s) in a few cups with different nutrients in them for a while, then drying the plants, weighing them and/ or testing for the amount of Fe or whatever nutrient that was in the plant/ in the water that it was grown in?

 

[Wet]

(I moved CL's posts and this threadjack of mine here from Tom's Phytometer thread in hopes we can make a practical test for this to actually see 'how long glucconate [and other forms of iron] "live" in our tanks')

Chris,

Sweet. Yeah, specifically Fe in both plant and water.

How exactly will you titrate and measure Fe from the plant tissue? If you can get this vs time with many different chelators, then what's in the water column and at what state (Fe +2 or Fe +3) doesn't really matter -- we can infer "available" Fe from whether the plants can still uptake it.

I don't think there's enough Fe in practical sizes of disposable plants to measure even on a mg scale and so accurate titration equipment for a hobbyist may be hard to source for cheap. We can totally titrate with KH2PO4, right? Might be too hard to tell. Is there something better you and/or your class would use?

I imagine a test that goes like this:

I want to know how long usable iron stays in solution. Say, we input .5ppm Fe from four different chelators/gluconate into 8 sets of samples, with 3 cups in each set. (3 cups a test, 8 tests. Each of the four chelators have 2 tests.)I want to know how much Fe (water column + plant mass) is in half of the sets after, say, 1 day. I want to know the same thing after 3 days.

Extra credit for another set per chelator so we can get 7 days. Extra extra credit if you can do it with more cups per set. (This would be an impractical number of cups for many of us.)

In addition to each of these tests, I want to copy Tom's point of a set of samples with non-limiting nutrients (I imagine this is adding, say, 1ppm Fe from a combination of the chelators daily) and another set of samples with DI water and no Fe. (These would also have to be measured after 1, 3, and 7 days.)

Other nutrients and light have to be the same across all sets dosed to non-limiting levels. To do this, I imagine these cups in a counter with unobstructed sunlight, then topped off every couple of days with a mixture of diluted KNO3 and KH2PO4 and Plantex. (I want FePO4 to precipitate out when making the mix to remove Fe input from Plantex. This should work as long as I mechanically filter the precipitate our and still yield non-limiting PO4 and all other traces in the water column before using this mixture to top off the cups.)

But I am not a scientist (obviously ) and am thinking of this as a guy who happens to like plants. I'm excited to see what other people come up with, especially Tom. What do you think of the above?

 

[CL_]

IDK if this has been posted, but apparently Fe gluconate breaks down fairly rapidly because the Fe doesn't have a strong bond to the gluconate (I think that's what it's called), but it is used in Seachem's flourish Iron because of the fact that it breaks down easily, the plants can have an easier time using the Fe ion in it. This was posted about 12 years ago over on thekrib
http://www.thekrib.com/Plants/Fertilizer/gluconate.html#2

Gluconate actually "complexes" the iron vs the "chelation" found with EDTA. The distinction between a complex and chelate is that there is no formal bonding in a complex which means that the association is not as strong as that found in a chelate. The problem with EDTA
chelation is that it is too strong and the plants have a very difficult time
"cracking the nut" to get the iron out. Gluconate complexation is not as strong so it is
much easier for the plants to extract the needed iron. Both chelates and
complexes give an overall charge neutral species. The gluconate also (like EDTA)
helps to keep the iron in solution longer than if the iron were free. However
because gluconate is not as strong as EDTA with respect to iron association you
will see some precipitation with Flourish Iron when dosing the tank... however
the key here is that more of the iron in Flourish Iron will be utilized by the
plants than will be utilized if EDTA-iron is used. The amount of EDTA-iron that
the plants are able to use is so small as to not really be useable. EDTA-iron
complexes look better to the consumer because it appears that after adding such a product to the tank the iron levels stay up for quite some time whereas with Flourish Iron the levels drop off more quickly (looks like the
EDTA-iron is more economical doesn't it?). However the Flourish Iron is being
utilized much more rapidly (and some of it is precipitating). I think the key here is to
see which product works best in your system. I'm confident that you would find that
Flourish Iron gives the best response. A third advantage to the gluconate is that it
is a reducing agent and so helps to keep the Fe+2 from being oxidized Fe+3 (the product also contains other reducing agents to aid in this process as
well). It is also my understanding that EDTA iron is actually in the +3 oxidation state.
>Greg Morin

looking at a drawing of an iron gluconate molecule, things are a bit more clear

(from wikipedia)
So, I'm sure I'm wrong, but it appears when it breaks down, you are left with
two 5(OH)02 with a -1 charge and the Fe2+ ion floating around? I'm sure I'm wrong, though.
Hope that helps, again, IDK if it has been posted already, though.