DIY Fertilizer Formula Recommendation

Hanuman

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In the video you posted you can see that it looks like paper pulp mixed in with the solution as a suspension, this is Zinc Hydroxide formation. The reason for this reaction is that the starting solution wasn't low enough on the pH scale, pH4.5 is too high, bring it down to pH2-2.5 and the Zinc Hydroxide shouldn't precipitate out and the solution will remain clear. If making an all in one I would make sure the solution is still quite acidic for if and when phosphate gets added at the end.
Thank you for that very insightful comment. I did read your adventure where you experienced the same issue and thought it wouldn’t happen to me. If I remember well you made the PH go down somewhere around 3 right?

Yes the suspension is an extremely fine powder. If you mix it takes several hours to settle back and drop to the bottom.

I think that my PH meter was off scale because I recalibrated the meter yesterday and tested the solution again prior trying all options and it was at PH3.5 so I think that initially the solution might have been around that. PH3.5 is still not low enough?

I will try again by making the solution more acidic. I suppose it’s just a mater of adding more ascorbic acid until reaching PH2-2.5 right?


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Zeus.

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In the video you posted you can see that it looks like paper pulp mixed in with the solution as a suspension, this is Zinc Hydroxide formation. The reason for this reaction is that the starting solution wasn't low enough on the pH scale, pH4.5 is too high, bring it down to pH2-2.5 and the Zinc Hydroxide shouldn't precipitate out and the solution will remain clear. If making an all in one I would make sure the solution is still quite acidic for if and when phosphate gets added at the end.

When I was formulating my traces I used two clear solution commercial mixes as a comparative, the first was Flourish Trace which had a pH of 2.7 and the second was Sera Flore DayDrops which had a pH of 2.15. When it came to the addition of Ferrous Gluconate, the commercial mix I was using had a pH of 3 in the bottle (Microbe-Lift Plants Fe), the powdered 11% FeDTPA I was adding also was tested for pH (made a solution in a separate bottle for pH testing) a mixture at a concentration for dosing at 0.5ml/10L for 0.25mg/L came out at a pH of 2.6 (water used was RO/DI 0TDS).

As a comparative Flourish Comprehensive has a pH of 4.3 in the bottle, I assume the reason for the higher pH is likely due to the humic acid content in the bottle, the Humic Acid based BioCo2 supplement I use has a bottle pH of 8.5, it's addition to a test amount of DIY trace with a pH of 2-2.5 climbs up to about pH4.5 afterwards when added at the correct dosing amounts, this is fairly inline with Flourish Comprehensive. The blackness and opacity of the resultant mixture makes it very hard to detect any precipitation if it has formed (same look and consistency of Flourish Comprehensive), when the bottle gets to the dregs at the end I can detect a slight creaminess to the liquid so there is some precipitation going on but it's very minimal (very consistent with Flourish Comp which does the same thing).

Make small batches to test the reactivity of the resultant solution, when you find a stable mix then you can scale up, I went for broke at the first shot and made 5L of trace that the zinc dropped out of, reacidifying just oxidised the Zinc Hydroxide in the solution making it completely unavailable (went from white paper pulp precipitate to a black dust).

:)
Think I might need to take more note when making my ferts, brush up on the chemistry and work on my potion skills. As the dump it all in a bottle and add RO may be leaving some elements unavailable to the plants. As X3NiTH aka 'The half blood Prince' does have his potions work out to some detail:clap:
 

X3NiTH

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:lol:;);)
If I remember well you made the PH go down somewhere around 3 right?
Yes, for 0.5g Ascorbic Acid in 900ml of RO/DI I was able to obtain a stable reading of pH3.2.

According to PubChem Ascorbic Acid has a pH of 3 at 5g/L, to bring it down to a pH of 2 you need to add 50g/L, for pH2.5 you'd need around 25g/L. Before I had dug into the pH characteristics of Ascorbic Acid I tried this experiment myself trying to shift the pH lower than 3 using Ascorbic Acid, I was tipping teeny little spoonfuls beyond the initial dose and not seeing much of a pH shift until it dawned on me that pH is a log10 function and I would need approximately a 10x weight increase to shift one point in pH, so I stopped addition deciding I'd rather save the Acid than waste it.

The commercial preparations that I mentioned that have a pH around 2 and will probably be using either Hydrochloric Acid or Sulphuric Acid to regulate the pH because they are more aggressive at lowering the pH, it's also probably a whole lot cheaper than Ascorbic Acid because you would need to use less product to shift the pH to a greater degree. A commercial product would need to guarantee a decent shelf life with zero precipitation in the bottle, hence the low pH I measured for them.

Whenever I mix up a batch of BuceJuce™ I always follow the same order of addition of elements (never all together and never before acidifying the receiving water). The order I decided on was the first salt added to the acidified RO/DI was going to be the element I wanted at the highest mg/L concentration in the resultant solution excepting the iron as I always add the iron at the end as it changes clarity and makes it harder to detect precipitation (if any) in the minor elements. I added and observed for dissolution and any resultant reaction. The order turned out to be MnSO₄ - ZnSO₄.7H₂O - H₂BO₃ - Na₂MoO₄.2H₂O - CuSO₄.5H₂O - NiSO₄.6H₂O - FeGluconate - FeDTPA 11%. There were no issues after mixing. The longevity storing at an average ambient temperature of 20c in a light fast 500ml dosing bottle (a few months supply) the solution remained problem free for at least 30days before it started to grow mould on the surface, when it got to below the last third of the bottle after a couple of months the solution was going slightly milky so I made a new batch, I followed the same order as above but this time stored the resultant solution in the refrigerator and used a smaller dosing bottle holding only a 20day supply to keep everything as fresh and reaction free as possible. The solution stored in the refrigerator is as good as the day I made it, crystal clear with a ferrous hue, this tells me that the mixture out of the fridge above 20c is possibly temperature sensitive over time (increased biological reactions?).

I will try again by making the solution more acidic. I suppose it’s just a mater of adding more ascorbic acid until reaching PH2-2.5 right?
Yes, although how much Ascorbic is too much I never tested out beyond doubling the dose and seeing no difference in reaction over the initial dose into RO/DI. If I were wanting longer shelf life and zero chance of precipitation I'd be using either of the acids I mentioned above, which one would depend on whether I wanted an extra Chloride content or a Sulphur one in the resultant mixture, either or both, I doubt it would make a huge difference to these levels, certainly not compared to the soup of extra elements acidifying down to pH2 with 50g/L of Ascorbic Acid would give you, I haven't tested so I don't know if that extra amount of Ascorbic would be fine when dosed to the tank.

I would add as much Ascorbic until the pH stopped shifting significantly (not far beyond pH3) and if possible use cooled water to make the mix and then refrigerate when done, you would need to test the solutions longevity at ambient temperature before precipitation/Mold issues are seen to give you an idea how long it will last out of he fridge in a dosing container. I haven't tested longevity in a completely sealed bottle that doesn't have access to ambient air like a dosing bottle would, but I have thought of packaging the ferts up in a sealed bag and dose like a saline drip would be relying on external air pressure to empty the bag, this would also keep it sterile and reduce the chance for microbes to grow in the solution.

@Zeus. :lol: Yes certainly I found this recipe to be a better targeted and less disfiguring PolyJuice Potion. Special note to commercial replicators 'Aguamenti Geminio!'

:bookworm:
 
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Hanuman

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I will will try with HCI. Easy to find and cheap. 25g/L of ascorbic acid might not be the best way to go indeed.
For mold prevention perhaps still adding potassium sorbate would still be ok right?
Also would HCI be a problem when doing an all-in-one solution or it’s just the same as ascorbic acid?


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X3NiTH

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Yes adding the KSorb should help with Mold prevention, I have it but don't bother to add it as I have still seen Mold formation when it's present in the mix, this was with a mix that sat for quite few months at ambient in a dosing bottle in non sterile conditions. I find the refrigerator does fine for storage between refills of the doser.

Can't really think of any problem using HCl in an all-in-one, it's just going to disassociate into free ions of H and Cl when it hits the water and drop the pH of the solution. It might be worth having a look to see how much you need to use to drop the pH to a requisite number and then calculate how much Cl it adds to the mix if only out of curiosity.
 

Hanuman

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Yes adding the KSorb should help with Mold prevention, I have it but don't bother to add it as I have still seen Mold formation when it's present in the mix, this was with a mix that sat for quite few months at ambient in a dosing bottle in non sterile conditions. I find the refrigerator does fine for storage between refills of the doser.

Can't really think of any problem using HCl in an all-in-one, it's just going to disassociate into free ions of H and Cl when it hits the water and drop the pH of the solution. It might be worth having a look to see how much you need to use to drop the pH to a requisite number and then calculate how much Cl it adds to the mix if only out of curiosity.
For testing purposes I will try doing a drop by drop addition in 100ml of water on a precision scale and testing PH at each drop. Then we can easily extrapolate for 500ml or 1L. I suppose that should do it?
 
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Zeus.

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:lol:;);)

Yes, for 0.5g Ascorbic Acid in 900ml of RO/DI I was able to obtain a stable reading of pH3.2.

According to PubChem Ascorbic Acid has a pH of 3 at 5g/L, to bring it down to a pH of 2 you need to add 50g/L, for pH2.5 you'd need around 25g/L. Before I had dug into the pH characteristics of Ascorbic Acid I tried this experiment myself trying to shift the pH lower than 3 using Ascorbic Acid, I was tipping teeny little spoonfuls beyond the initial dose and not seeing much of a pH shift until it dawned on me that pH is a log10 function and I would need approximately a 10x weight increase to shift one point in pH, so I stopped addition deciding I'd rather save the Acid than waste it.

The commercial preparations that I mentioned that have a pH around 2 and will probably be using either Hydrochloric Acid or Sulphuric Acid to regulate the pH because they are more aggressive at lowering the pH, it's also probably a whole lot cheaper than Ascorbic Acid because you would need to use less product to shift the pH to a greater degree. A commercial product would need to guarantee a decent shelf life with zero precipitation in the bottle, hence the low pH I measured for them.

Whenever I mix up a batch of BuceJuce™ I always follow the same order of addition of elements (never all together and never before acidifying the receiving water). The order I decided on was the first salt added to the acidified RO/DI was going to be the element I wanted at the highest mg/L concentration in the resultant solution excepting the iron as I always add the iron at the end as it changes clarity and makes it harder to detect precipitation (if any) in the minor elements. I added and observed for dissolution and any resultant reaction. The order turned out to be MnSO₄ - ZnSO₄.7H₂O - H₂BO₃ - Na₂MoO₄.2H₂O - CuSO₄.5H₂O - NiSO₄.6H₂O - FeGluconate - FeDTPA 11%. There were no issues after mixing. The longevity storing at an average ambient temperature of 20c in a light fast 500ml dosing bottle (a few months supply) the solution remained problem free for at least 30days before it started to grow mould on the surface, when it got to below the last third of the bottle after a couple of months the solution was going slightly milky so I made a new batch, I followed the same order as above but this time stored the resultant solution in the refrigerator and used a smaller dosing bottle holding only a 20day supply to keep everything as fresh and reaction free as possible. The solution stored in the refrigerator is as good as the day I made it, crystal clear with a ferrous hue, this tells me that the mixture out of the fridge above 20c is possibly temperature sensitive over time (increased biological reactions?).



Yes, although how much Ascorbic is too much I never tested out beyond doubling the dose and seeing no difference in reaction over the initial dose into RO/DI. If I were wanting longer shelf life and zero chance of precipitation I'd be using either of the acids I mentioned above, which one would depend on whether I wanted an extra Chloride content or a Sulphur one in the resultant mixture, either or both, I doubt it would make a huge difference to these levels, certainly not compared to the soup of extra elements acidifying down to pH2 with 50g/L of Ascorbic Acid would give you, I haven't tested so I don't know if that extra amount of Ascorbic would be fine when dosed to the tank.

I would add as much Ascorbic until the pH stopped shifting significantly (not far beyond pH3) and if possible use cooled water to make the mix and then refrigerate when done, you would need to test the solutions longevity at ambient temperature before precipitation/Mold issues are seen to give you an idea how long it will last out of he fridge in a dosing container. I haven't tested longevity in a completely sealed bottle that doesn't have access to ambient air like a dosing bottle would, but I have thought of packaging the ferts up in a sealed bag and dose like a saline drip would be relying on external air pressure to empty the bag, this would also keep it sterile and reduce the chance for microbes to grow in the solution.

@Zeus. :lol: Yes certainly I found this recipe to be a better targeted and less disfiguring PolyJuice Potion. Special note to commercial replicators 'Aguamenti Geminio!'

:bookworm:
:eek::woot::clap::clap::clap: and thank you for sharing the details :thumbup:.
I have to admit that my ferts do go a bit cloudy near the end.
Do like the idea of keeping the fert in the fridge, no room in fridge but do have space in freezer in garage, think that should do the trick as well !
 

Hanuman

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I'd be using either of the acids I mentioned above, which one would depend on whether I wanted an extra Chloride content or a Sulphur one in the resultant mixture, either or both, I doubt it would make a huge difference to these levels,
All my research so far has lead me to find information about what acids are mostly used in fertilizers. It seems that Sulfuric acid, Phosphoric acid, Nitric Acid or Citric acid are the ones that come up the most.

Looking into Hydrochloric acid it doesn't seem to be used that much or perhaps my research is flawed. Perhaps the Chlorine content of it?

In any case is there a calculator out there what would allow me to calculate the ppm values that each of these acids add to the solution? Rotalla or Zorfox don't include these acids.

and then calculate how much Cl it adds to the mix if only out of curiosity.
How would I calculate the CI content?
 
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dw1305

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Hi all,
It seems that Sulfuric acid, Phosphoric acid, Nitric Acid or Citric acid are the ones that come up the most.
It is "bang for buck" really, sulphuric (H2S), nitric and hydrochloric acids are strong acids and you only need a very small amount of acid to reduce pH.

Citric acid (C6H8O7) is a lot safer (it is weak acid) and may promote plant growth. It is also a weak chelator of iron etc.

Nitric acid (HNO3), or phosphoric acid (H3PO4), are usually the preferred option in commercial hydroponics etc., because they supply some macro-nutrients. You are going to be injecting really small volumes of acid, and monitoring the pH very carefully.
Looking into Hydrochloric acid it doesn't seem to be used that much or perhaps my research is flawed. Perhaps the Chlorine content of it?
In older literature it is refrred to as "muriatic acid". It isn't ideal because it is a strong acid, so it disassociates fully, and pretty much instantly, into H+ and Cl- ions. You have to very careful with it, it is extremely corrosive.
How would I calculate the CI content?
Same as any other compound, you need the RAM of the elements and RMM of the compound. In this case H = 1 and Cl = 35.5 and the RMM = 36.5, so ~97% Cl.QUOTE="Hanuman, post: 575974, member: 17975"]In any case is there a calculator out there what would allow me to calculate the ppm values that each of these acids add to the solution?[/QUOTE]Not really, there are theoretical formula based on the disassociation content (pKa), but I'd strongly advise against using strong acids to reduce pH.

cheers Darrel
 

Hanuman

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Thanks Darell.
But why do you advise against it? Thought you suggested to use some earlier. Any issues other than the risk associated with those strong acids? And what about sulfuric acid?





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zozo

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Citric acid (C6H8O7) is a lot safer (it is weak acid) and may promote plant growth. It is also a weak chelator of iron etc.
I still have a Kilo of this stuff (Powder) in the kitchen. But actually never came to my mind to add to the aquarium together with the dry salts. :)

How does one determine the proper dose? The initial pH drop?.
 

zozo

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Thanks Darell.
But why do you advise against it? Thought you suggested to use some earlier. Any issues other than the risk associated with those strong acids? And what about sulfuric acid?





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There are some references to find from people using vinegar in their planted tanks. I guess it's discovered accidentally using it as a cleaner to remove stains from the glass. It seems they found that it promotes plant growth by adding a regular dose.
http://scapefu.com/dosing-vinegar-in-your-aquarium/

I have no personal experience other than using it to clean the glass. But it seems to work.

Tho if your reason of using acids is a steady Ph drop i guess you're playing with dangerous stuff. Since the carbonates buffer acid, the pH drop will never be constant and go down and up again. Then at a certain amount of strong acid (1ml to much), you will reach a buffer threshold and the pH will shoot down dramatically. This treshold is very hard to determine.

Give it a try with some tap water.. Drip the acid in it and monitor the pH. You might need to add quit a lot for the first 1 unit drop. Then it becomes significantly less to fine tune and make it drop further. Then if you reach the threshold 1 drop acid can be enough to make the ph drop 2 units and bellow a safe value.
 
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zozo

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Beyond that aspect, is there any reason why not to use HCl.
I little guess is simply because it's too aggressive. :) And using weaker acids is easier to fine-tune the final result. Since pH is a log to the power 10, then using a stronger acid you need significantly less and makes it difficult to work with small volumes.. And as explained above with strong acids 1 drop too much can crash the Ph. Then if 1 drop is to much how are you going to measure 1/10 of a drop? Then if you are to low you need to add e.g. KOH again to make it rise. That's also something you don't really like to play with too much.

But in the horticulture, it is pretty common to use products that contain 17% HCl, 3% and Nitric acid to regulate pH in the growing season. And 59% Phosphoric Acid in the blooming season. It's not used as preservation but to get the fert solution to ideal pH value, but then you are talking making vast quantities of fertilizer mix to water the plants.

If you like to regulate pH in 500ml solution it's more practical to use a weaker acid.
 

Hanuman

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I appreciate all the answers and precautions but reading my previous exchanges with @X3NiTH and @dw1305 might shade some light on why these acids came to the discussion in the first place and why they could be needed. Obviously I will not just start adding blindly some acid by the liters. I was planning to run different tests first with some plain RO water see how HC was going to change and settle. I might not be a chemist but I am well equipped and take great care with chemicals. I got graduated pipettes, beakers, stir roads etc. In fact today I went ahead and bought some HCl and some H2SO4 but I think I went overboard on the strength. Thinking it twice I should have taken half strength (6 mol) as it will allow me easier control on PH. I might return the bottles tomorrow and exchange them since I didn't open them yet. And for those questioning why I got 400cc of acids, well the answer is simple. There was no lower quantities sold. I was looking for 100cc or even 50cc but none of the shops I enquire had those quantities. Also note the difference in levels between the two bottles. Seems I also got robbed :lol: or perhaps got more in one bottle. Wont be emptying the bottle to check that's for sure!!

IMG_2146.jpg


Beyond that, weaker acids like the one I have been using (Ascorbic Acid) have their limits and if one wants to bring PH below PH3 one would need to add copious amounts which might not be the best thing to do. @X3NiTH explains it well a few posts above.
 

Zeus.

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It's been a while since studying chemistry (so might have it wrong!)
But think it's to do with HCL and H2So4 are simple acids so give up their H+ quite freely hence the big pH drop for given [molar], where as Citric acid is more complex so doesn't give up as many H+ as the simple acids at same [molar]. So when using simple acids you get bigger pH swings when added and as the H+ ions get mopped up, where as the complex acids give a small pH swing but as the H+ ions get mopped up the complex acids release more H+ ions due to the change in equilibrium so the complex acids have more buffering capacity- and help maintain a more stable pH, therefore better for tank
I could be wrong and I'm sure on if the guys will correct me if I am ;)
 

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