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CaMg(CO3) aka Dolomite for remineralization?

Actually here’s a graph for Iron EDTA

6010ADAF-E84A-4C03-9A62-E4B76F1E850C.png

Note that most Iron Chelate complexes we use are usually between 9% and 13%, 11% being very common. Also note the graph is for a concentrate and not very highly diluted tank dose in the sub parts per million.

Here’s the graph for the chelate availability as a function of pH.

0F9C05ED-0541-4780-BC5D-C29E778A0694.png

🙂
 
X3NiTH said:
Here’s the graph for the chelate availability as a function of pH.

View attachment 174718

🙂
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Hi @X3NiTH Fascinating... That is indeed a very steep negative gradient for EDTA... It would be great to be able to see a curve for the realistic ppm availability, that we are facing, over time given the dosing at a certain pH. Reading up on the topic (mostly less applicable agriculture related research) I get the impression that you pretty much don't have any iron available for the plants at a pH of +7.0 after a very short amount of time ... which sounds very unlikely as most of our tanks would have a severe Iron deficiency if so.

Cheers,
Michael
 
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X3NiTH said:
You can null test for biological reactions by using a sterile environment using the same water chemistry as in the tank but hasn’t seen any biological processes, dose the additives and check for reactions, if there is a reaction then it’s a chemical process.
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Hi @X3NiTH

I'd be interested in knowing more about how you create a sterile environment. This is something that I've tried in aquatics but in a different situation. I was trying to create an environment in which nitrification could not occur. If my memory serves me well, I kept pH well below 7.0 and made no attempt to reduce lighting. I do believe I also ran a UV-C sterilizer throughout the experiment. I'll try to dig out my notes to confirm these details. Obviously, the use of a UV-C sterilizer is not possible if dissolved organics and iron are critical to the experiment.

JPC
 
jaypeecee said:
Hi @MichaelJ

Doesn't the addition of the potassium ion raise GH?
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Hi @jaypeecee It definitely raises the conductivity (TDS). When I measure the GH of my softened tap water with the API Test Kit it is consistently "zero". That is, it I see a change reaction on the first drop. if I increase the test tube to 10 ml instead of 5 ml, I still get a reaction on the first drop, so I assume it's very close to zero or 0.5 GH at most. Last time I checked the city water that is fed into our house it was somewhere around 12 GH/12KH - it can vary quite a bit over the year actually - I have measured ~20 GH at some point (didn't measure KH at that time - the GH and KH always measures very close here).

I believe from the ion exchange in the KCL resin we end up with about 14ppm of K+ for each 17ppm of CaCO3. So in our case our softened water contains 168 ppm of K. I usually mix in around 30-40% tap-water to my WC mix which is essentially the only source of K I provide my tanks... but that's 50-67 ppm of K per week, but could be as much as 112 ppm of K per week at times when the GH/KH is in the 20 range...

EDIT: Another thing that I haven't quite figured out (or forgot about); Is that the softened water still comes out at 12 KH... (and "zero" GH as said), but when I mix it in with my RO water and do WCs I read about 3-4 KH (30-40% tap/ro mix) - as excepted, but when I measure my tanks after a day or two after WC I never see a KH reading above the 1-2 KH range.

Cheers,
Michael
 
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Hi @MichaelJ

It's just dawned on me that you must be using an ion-exchange resin to soften your water. I was thinking that you simply added KCl to your tap water. My bad! 😕

JPC
 
jaypeecee said:
Hi @MichaelJ

It's just dawned on me that you must be using an ion-exchange resin to soften your water. I was thinking that you simply added KCl to your tap water. My bad! 😕

JPC
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Oh I see. It is indeed an iron-exchange resin based water softener. All the tap water inside our house is softened - including the kitchen, which I believe is usually excluded by law in Europe.

Cheers,
Michael
 
Hi all,
jaypeecee said:
Doesn't the addition of the potassium ion raise GH?
Click to expand...
No, K+ a monovalent cation, and dGH is a measure of multivariate cations.
MichaelJ said:
It definitely raises the conductivity (TDS).
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It will do, because basically you've swapped one Ca++ (or Mg++) ion for two K+ ions. The cation exchange is <""Strong Acid" exchange"> so the anions remain unchanged, but both CaCl2 and K(H)CO3 are soluble salts, so you don't get "scale" deposits.

cheers Darrel
 
Hi all,
jaypeecee said:
I dug out the following - just in case anyone wanted to read a bit more. It's a 'conversation' between members of The Krib from 23 years ago, including Dr. Greg Morin...

Iron gluconate
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I'm not sure Dr Morin's comments add a lot, in many ways it just reads like a precursor to Seachem's later advertising campaigns. This is what Dr Morin says about FeEDTA.
....... Caution was urged as overdosing E.D.T.A could lead to the nutrients actually being sucked out of the plants, leading to collapse. Most of us, when dealing with E.D.T.A., use it in a form where it has already been associated with the nutrient ions." This is the crux of the matter. If EDTA sucks nutrients (cations) out of plants, how likely is it that if one adds EDTA with a nutrient (Iron) that the plant is going to pluck it right back? If the EDTA can pull the nutrients out, then clearly the EDTA is the stronger of the two in this tug of war...
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and this was the reply from "Roger Miller":
....... EDTA-chelated iron (as well as DTPA chelates and a few others) have been in horticultural use for decades with a record of apparent effectiveness. Either the chemical industry has foisted a huge hoax on the agricultural, horticultural and hobby industries and we've all been naively duped or EDTA chelated iron is biologically useful. I tend to think that EDTA-iron is useful.
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and "erewobe" from the University of Manitoba:
....... No, in countless experiments over many years, research has clearly shown that chelated Fe:EDTA can deliver adequate amounts of iron for maximal growth rates. In my own experiments I have found that 0.2 to 0.9 uM FE:EDTA (0.1 to 0.5 ppm) will suppport relative growth rates of between 75 to 300 (1 to 4 day doubling time)........
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and they pretty effectively dismantle him and his argument. This was from Karen Randall
I'd suggest that people do what I usually advocate anyway. Watch your plants. If they look like they are suffering from an iron deficiency, (which, BTW, won't show up as slower growth at first, but as chlorotic new leaves. This will be apparent in fast growing plant species first)..........
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cheers Darrel
 
dw1305 said:
Hi all,

No, K+ a monovalent cation, and dGH is a measure of multivariate cations.

It will do, because basically you've swapped one Ca++ (or Mg++) ion for two K+ ions. The cation exchange is <""Strong Acid" exchange"> so the anions remain unchanged, but both CaCl2 and K(H)CO3 are soluble salts, so you don't get "scale" deposits.

cheers Darrel
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Hi Darrel, Thanks for that.. I think I understand the Ca/Mg part as it pertains to GH. So the reason I am still measuring ~12 KH in the softened water is because my (API KH) test kit is essentially measuring the CO3 and not CaCO3 content. Since whatever CaCO3 I had in the un-softened water turns into KCO3 ?

Could this also somehow explain why I usually see a drop in KH when I measure a day or two after WC?

Cheers,
Michael
 
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Hi Darrel (@dw1305)

dw1305 said:
I'm not sure Dr Morin's comments add a lot, in many ways it just reads like a precursor to Seachem's later advertising campaigns.
Click to expand...
dw1305 said:
...and they pretty effectively dismantle him and his argument.
Click to expand...

Do I therefore take it that FeEDTA is every bit as good as ferrous gluconate? Indeed, is the latter inferior to FeEDTA?

Thanks in advance.

This is good stuff. I know very little about chelators.

JPC
 
Dr. Morin: 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.
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I thought that was an interesting comment - but appears to be less of a concern.
X3NiTH said:
I dose 0.1ppm FeGluconate and 0.05ppm FeDTPA together and 24hrs later I measure 0.025ppm which will be very likely all FeDTPA, still enough to cover the plants for the day until a new dose goes in 24hrs later. You always want some available to ensure no deficiencies, you appear to be accomplishing this with your current dose.
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I think @X3NiTH's approach of hedging the bets on Iron availability is worth considering, especially if we are dosing EDTA and are running our tanks close to or above 7 pH or when other factors that may prevent optimal utilization of the iron exists (I.e. running UV filters - which may or may not be a problem).

0f9c05ed-0541-4780-bc5d-c29e778a0694-png.png

Regards,
Michael
 
Hi all,
jaypeecee said:
Do I therefore take it that FeEDTA is every bit as good as ferrous gluconate? Indeed, is the latter inferior to FeEDTA?
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Ferrous gluconate is a "weaker" chelator than FeEDTA, so Fe++(+) ions are more available, but also more likely to form insoluble compounds. It probably all comes down to how hard your water is. In very soft water you can add ferric chloride (FeCl3.nH2O) and those Fe+++ ions will remain plant available, but in harder water they are going to be mopped up and form <"insoluble oxides, hydroxides, carbonates and phosphates">.
X3NiTH said:
You likely need to dose an Iron chelate that is more appropriate for this water hardness and pH, for longer term persistence something like DTPA or EDDHA works well, alternatively you can dose more of a shorter term chelate Iron supplement like Ferrous Gluconate which can quickly break down but is highly plant available and full of nutrition, the Gluconate chelate is a fully biodegradable long chain carbon molecule.
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* edit What @MichaelJ says.

cheers Darrel
 
Hi all,
Hufsa said:
has experienced some plants doing better when using both DTPA and gluconate
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I can see you might have a situation where a combination might be of value, but it would be a pretty marginal gain and largely aesthetic.

I actually add FeEDTA on a fairly regular basis now, purely because Fe deficiency is where the <"Duckweed Index"> has some limitations, in that by the time the <"deficiency is obvious">, it takes a while before new, healthy leaves grow.

If you look at @Zeus. 's <"Future of aquascaping"> image, you can see what can happen as iron availability is turned off and on.

cheers Darrel
 
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