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K2hPo4 mixing with CSM+B

Gorillastomp

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I have read at many place that you can't mix PO4 and Iron at the same time unless the PH of the solution is acidic. Maybe i read it wrong.

Yesterday i wanted to test that out because i front load my Water Change to desired ppm and wanted to see if i could mix my trace at the same time.

I did add everything(Kno3,K2HPo4,K2So4, MGso4) in my 2L bottle to make the solution including the trace. The end solution was crystal clear.

So i do not understand this, wouldn't the iron precipitate out of the solution doing so ?

My water PH was 8.3 for the solution.
 

MichaelJ

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I have read at many place that you can't mix PO4 and Iron at the same time unless the PH of the solution is acidic. Maybe i read it wrong.

Yesterday i wanted to test that out because i front load my Water Change to desired ppm and wanted to see if i could mix my trace at the same time.

I did add everything(Kno3,K2HPo4,K2So4, MGso4) in my 2L bottle to make the solution including the trace. The end solution was crystal clear.
Hi @Gorillastomp Good question. What kind of Chelate is in your trace mix? It seems it might depend on the Chelate and the concentration of P/PO4 and the Fe trace amount and pH... I still get occasional cloudy water when I dose Fe Gluconate in one of my tanks. When I dose EDTA based traces I never get cloudy water in either tanks... I do not know if the precipitation might still occur even if the solution/water is not getting cloudy. I usually dose my traces the day after or at least 10-12 hours after the WC just to error on the safe side. I have no signs of Fe (or any other) deficiencies in my tanks.

Cheers,
Michael
 
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Gorillastomp

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What kind of Chelate is in your trace mix?
On the package it state there is EDTA and DPTA Chelate but it doesn't specify which one is for the iron. It state that the concentration of iron is at 7% so i would assume its using the 7% Fe DPTA.
the concentration of P/PO4 and the Fe trace amount and pH
The solution would have had 1000 ppm po4 and 87 ppm Iron and Ph is at 8.3

I do not know if the precipitation might still occur even if the solution/water is not getting cloudy.
My understanding would be that it create some dust that would make it unusable to the plant.
 

MichaelJ

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On the package it state there is EDTA and DPTA Chelate but it doesn't specify which one is for the iron. It state that the concentration of iron is at 7% so i would assume its using the 7% Fe DPTA.

The solution would have had 1000 ppm po4 and 87 ppm Iron and Ph is at 8.3
hmm... I am not sure about mixing the PO4 and Iron in a high pH solution? I wouldn't do that. I would dose the compounds separately... I want to hear what the Chemistry / fert gurus say about this one?

What brand of traces are you dosing btw?

My understanding would be that it create some dust that would make it unusable to the plant.
Yep, that pretty much how I look at it as well :)

Cheers,
Michael
 
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Yugang

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I struggled with similar question, hence my recent post
Trying to reformulate my question in general terms, rather than for my specific tank (I dose all Macros and Micros from separate bottles, just to be sure):

“What salts can be mixed in an All-In-One solution (without significant adverse reactions that may limit nutrient availability for plant uptake), and what are the exceptions where there is a need to keep salts separate in multiple dosing containers and/or dose at separate times into the tank?”

With my very limited knowledge of chemistry, I am trying to understand what seem to be two different cases with different dynamics:
  1. The dosing containers with relatively high concentrations of salts mixed and dissolved in water; these can potentially interact for weeks or months until the container is empty and will be replenished. This combination of high concentration and longer timeframe seems a worst case scenario from a adverse chemical reaction perspective.
  2. Our tank where salts are diluted down to ppm levels, and where the typical times for unwanted chemical interactions to take place are hours/days (the time between fresh doses into the tank). This raises the question whether it is indeed beneficial to dose different fertilisers on separate days if the objective is to mitigate potential chemical interactions between them.
I am hoping that there is a resource, or a brilliant chemist amongst us who can supplement this information to the IFC calculator.

From the replies on above posting I got valuable advice, but I believe there is still an opportunity for a chemist to clarify/quantify to what extent interactions are significant to our hobby - as it also relates to OP question.

Doing some more research, I learned from another forum (from Greggz on Planted Tank Forum, with reference to T Barr / 'Is there a point dosing macros and micros on alternating days?') that as we have low concentrations in the tank water, the interactions between the macros/micros will be too small te be relevant to the hobby. Greggz and T Bar seem very credible to me.

Most likely, my own guess, the high concentrations in dosing bottles are an entirely different situation. For the dosing containers the general advice is not to mix micros and macros.
 

Gorillastomp

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What brand of traces are you dosing btw?
i am using AAAquatic brand. Their website is currently down so not sure if they are more specific there. I can only refer to my label at the moment.

that as we have low concentrations in the tank water, the interactions between the macros/micros will be too small te be relevant to the hobby.
the solution would have had 1000 ppm po4 and 87 ppm Iron and Ph is at 8.3

What would be considered low concentration ? Because in my 2L bottle there was no precipitation.

I still get occasional cloudy water when I dose Fe Gluconate in one of my tanks.
I was using Aquavitro version of Iron at the beginning of my tank because i didn't know back then about dry ferts. If i remember correctly they are using Fe gluconate in it and oh boy my tank was cloudy after dosing that. Took me a bit to figure out it was that.

Never had cloudy water since i am using the dry ferts but i have always dosed Macros and Micros with a 4 hours gap. Now i am just not sure if this is actually necessary after my experiment. Maybe with a different chelate it would be another story.

There's another thing that i do not understand about the alternative day macro/micro, there is still po4 in the water when dosing the micro on the next day. I guess if it was the case it would precipitate even there which is not happening.
 

dw1305

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Hi all,
On the package it state there is EDTA and DPTA Chelate but it doesn't specify which one is for the iron. It state that the concentration of iron is at 7% so i would assume its using the 7% Fe DPTA.
That sounds likely. If you keep the solution in the dark you shouldn't get much photo-degradation of the chelates. If the iron remains chelated there aren't any iron (Fe++(+)) ions to form insoluble iron hydroxide, oxide and phosphate compounds. As soon as the iron ions become available they will be mopped up and precipitate out.
I am not sure about mixing the PO4 and Iron in a high pH solution? I wouldn't do that. I would dose the compounds separately... I want to hear what the Chemistry / fert gurus say about this one?
No, I definitely wouldn't, you ideally need to keep the PO4--- and Fe++(+) ions apart. If you don't get any visible precipitate over time? You are probably OK.

The easiest option is for you to just to add some citric (C6H8O7), ascorbic (C6H8O6) or acetic (CH3COOH) acid to the "All - in - One" solution to reduce the pH. Once you are comfortably below pH 7 most of your problems just go away.

file-TjRiGNYWdw.png


The advantage of the weak acids listed is they only contain carbon (C), hydrogen (H) and oxygen (O), so you aren't adding any "extra" nutrients.

cheers Darrel
 

Gorillastomp

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@dw1305 So the chelate degradation only happens when its in contact with light ? At what pace the degradation would happen ? are we talking minutes, hours, days or weeks ?

The easiest option is for you to just to add some citric (C6H8O7), ascorbic (C6H8O6) or acetic (CH3COOH) acid to the "All - in - One" solution to reduce the pH. Once you are comfortably below pH 7 most of your problems just go away.
Just to clarify my point, i am not making an AIO solution that i keep on the shelf. I just poor everything in a 2l bottle to mix it up at my WC then drop it in the tank right away to bring back my water to desired ppm. I always feared to add the micro to that mix because of the said precipitation which seems to not happen from my experiment.
 

dw1305

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Hi all,
So the chelate degradation only happens when its in contact with light ?
It does, I've no real idea of the timescale.
I just poor everything in a 2l bottle to mix it up at my WC then drop it in the tank right away to bring back my water to desired ppm.
Just carry on, that is so close to dry dosing so you probably aren't going to get any issues.

cheers Darrel
 
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Yugang

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The easiest option is for you to just to add some citric (C6H8O7), ascorbic (C6H8O6) or acetic (CH3COOH) acid to the "All - in - One" solution to reduce the pH. Once you are comfortably below pH 7 most of your problems just go away.
Is it correct that white household vinegar would be Acetic? Does 10 ml on a 500 ml dosing bottle sound reasonable?
 
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