I forgot - here is a pic of the original cloudy sample on the left and the new clear sample on the right. Not much difference.
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Made up a batch of 1M KOH base (PH up). Titrated Megacrop with no buffer and Megacrop with a MES buffer:
Buffering increased nearly 9X in the region of interest for a 10 mMol MES buffer.
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Yeah I was going to say an order of magnitude improvement.
I checked my cost on MES hydrate â about $3 per gram though, hella priceyâŚ
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MES free acid can be had for ~0.13/g bulk kilogram quantity, currently. Still much more expensive than some of the alternatives.
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Better! Still burns though⌠did you titrate with NaOH for the buffer pH in the megacrop solution?
I wonder if a citrate can be used for cost savings?
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Very interesting result. Im guessing one big reason for Advanced Nutrients PH Perfect line being so $$$ is that they use MES as a buffer. They may have other stuff in there as well.
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That comes out to about $38 for 40 gallons at the 10mMol concentration. Literature claims adverse effect for more than 20-30mMol in practice for nutrient solutions. This could be related to the tendency for the MES to bind certain nutrients, as @Doulovebeef alluded to. 10mMol may still be a bit strong. Donât really know as I havenât researched it enough. Reducing the concentration may work just as well in practice.
Both of the solutions were titrated with KOH in the plot. A strong base. Very similar to NaOH, difference being the molecular weight (K vs Na). Is that what you are asking?
Yes, citrate buffer would be much more inexpensive. There are several other potential buffers planned (list in the OP) including a citric acid/citrate buffer. Or, if there are other ideas we can consider. Doubt theyâll perform as well but perhaps we will be surprisedâŚ
I donât know what they are using. May be related to the patent (absurd) that I had posted, if thatâs them. AN has some ridiculous markup on most everything as far as I can tell. I doubt theyâd be at 10mMol concentration in any case.
Oh, should note, this is the Megacrop legacy formula.
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On the cloudiness.
This last test I ran, using the strong base, had some precipitation at around the same PH as before ~7.5. But, perhaps not as great of an amount. Also, this time it was more tan and fluffy. This occurred in both in the plain MC and the MC + MES solutions.
Bringing the PH back down redissolved most of the precipitant though the solution remained slightly cloudy, similar to your photo.
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Chemistry discussion.
Enter the mole, Molarity, what the F?
For those interested, 1M is the abbreviation for 1 Molarity which is also an abbreviation for 1 mole/liter. A mole is a standard term used in chemistry to âcountâ the number of molecules/atoms/photons/whatever of a substance. Molarity is based on the mole and is standardized to mean the number of moles in one liter of solution. When you go online reading papers, particularly scientific papers, or if you want to purchase some sort of solution, moles and Molarity are very common units.
Uggh. Stay with me, this sounds confusing but it will become easier in a moment.
As an aside, when you see the term umols when looking at lights, its the same thing. Moles (mols), and âuâ meaning divided by one million. They are just counting photons instead of molecules
One mole of a substance contains 6.022 x 10^23 âparticlesâ. This is Avagadroâs number. So, for 1 mole, weâd have 6.022 x 10^23 âparticlesâ. If we have 6.022 x 10^23 molecules of a chemical, letâs say KOH, we can say that we have 1 mole of KOH. And, since KOH disassociates into K+ and OH-, we can also say that we have 1 mole of K+ and 1 mole of OH-. By placing this into 1L of a solvent, we can say that we have a 1M KOH solution.
This sounds complicated but in practice itâs straight forward. We hide Avagadroâs number in the atomic mass and come back to it later. Letâs try an example.
How many moles is 1 grams of sulfur?
We can calculate the number of moles of a substance by the atomic mass of the substanceâs molecule and the total mass of the substance. For instance, if we have 1 gram of elemental sulfur, we would first determine itâs atomic mass (grams / mol). Here are the numbers youâd find on a periodic table:
From the table we see that sulfur has an atomic mass of 32.06
So, with 1 gram we have (1 / 32.06) = 0.031 moles of sulfur.
If we were able to dissolve this into 1 liter of a solvent, weâd have a 0.031 molarity or a 0.031M solution.
How many moles is 20 grams of potassium hydroxide?
Potassium hydroxide is KOH. Three single molecules.
Referring back to the table, K = 39.0983, O = 15.9994, and H = 1.0079. Add these together for a total mass of 56.11.
This tells us weâd need 56.11 grams of KOH for 1 mole.
Since we have 20 grams, (20/56.11) = 0.35 moles of KOH.
Put this into 1 liter of water, weâd have a 0.35M of KOH solution.
What if I want to make 500mL of 1 Molarity solution using 90% pure KOH?
For a 1M solution of KOH, we calculate it as follows:
Recall, K = 39.0983, O = 15.9994, H = 1.0079 (from the table above 
). Add them and the molecular weight = 56.11 g/mol.
The volume is 0.5 liters of solution.
The purity of our reagent is 90% as purchased.
Grams of KOH needed = ((56.11) * (0.5)) / 0.90 = 31.17 grams for 500 ml 1M KOH.
Since the purity of the reagent is 90%, there will be 10% of some unknown stuff in solution. But, we do know for certain that we will have the 1M of KOH in our solution.
Ok, so I have 1 liter of 1M KOH solution, how many OH- ions are in there?
Recall, Molarity (M) means moles per liter.
Recall, KOH disassociates into equal amounts of K+ and OH- in solution.
We have equal amounts of both, so we also have 1M of K+ and 1M of OH-.
Avagadroâs number is back in play. Recall, 6.022 x 10^23 âparticlesâ/mol.
Since our solution is 1M and the volume is 1 liter, we therefore have 6.022 x 10^23 OH- ions. Thatâs a helluva lot.
Ok, so I take 500ml out of 1 liter of 1M KOH solution, now how many OH- ions do I have?
Simply, using the previous result, (0.5L/1L) * 6.022 x 10^23 OH- ions = 3.011 x 10^23 OH- ions.
Half as many.
Why would I care about OH- ions? Or, H+ ions?
OH- and H+ ions determine PH. In equal amounts, the PH is 7.0. If there are more H+ than OH- ions, the solution is acidic. Conversely, more OH- than H+ ions and the solution is basic. With a bit of work, we could calculate the PH of a simple solution by knowing how many H+ and OH- ions are available.
Fun:
What is the concentration in moles for the population of the United States?
2019 population is estimated at 328,005,208.
There are 6.022 x 10^23 âparticlesâ per mole.
(328,005,208) / (6.022 x 10^23) = 5.45 x 10^-16 moles. Thatâs small, relative to our 1M KOH solution.
What is the concentration in moles for the population of the World?
2019 population for the world is ~7,700,000,000
(7,700,000,000) / (6.022 x 10^23) = 1.28 x 10^-14 moles. Still exceedingly small.
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Just received, 20-200 uL pipette $40 off Ebay. 
Also received a couple of glass pipettes, and as @Tinytuttle noted, the control was terribly difficult. Would have to dilute a solution a huge amount to retain any accuracy. Hopefully thisâll do better.
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Weâre they the ones you put a bulb on the end with a squeeze release valve?
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u gotta have to right tools, the pipette was a very nice find on ebay!
its interesting to me that the precipitate is tan, all precipitants for Ca, Mg are white. any chance we can filter and wash the precipitants with cold water to verify they are indeed tan?
if it is magnesium the precipitate will go back into solution with the addition of ammonia.
ammonia has no noticeable reaction if the the precipitate is Ca.
my next thought was it was the chitosan that is included in the formula. chitosan will increase precipitation with the increase of PH, but does not go back into solution when the PH decreases.
this is all assuming that the precipitates are caused by the KOH.
i was reading through this link and if you scroll all the way down âpeter jacksonâ lists out a protocol for the buffer. maybe something to compare your protocol with?
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Next time I see it, Iâll filter it off. Though, washing it with cold water may be an issue since it seems mostly soluble at less than 7.5 or so.
For reference (MC only titration, no MES):
High PH stiring (10+):
High PH not stiring (10+):
PH lowered to ~7:
For MES, pretty much the same idea as far as I can tell. He has a higher concentration of MES free acid and is using a conjugate base to adjust the target PH as opposed to using the more nasty KOH/NaOH. Which may be an option as the initial PH up when running a live system. For plotting the titration curve, donât know if it really matters since we are looking to adjust the H/OH ratio. Though, if there is a technical error with this thinking, Iâm all ears.
edit: One thing that caught my eye from reading that link is how he says âvolumeâ doesnât matter. Which is a bit misleading the way it reads but I think what he is trying to say is important. Need to relate this back to reality when we consider âhowâ much buffer ingredient is actually needed in a real system. Weâre talking quantities of the OH and H+ and how it changes over time. Will get back to this.
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Yes, with a pipette pump instead of a bulb. A better description would be âtime consuming deviceâ.
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So since megacrop has changed its ingredients does this thread even matter anymore? I can say though from testing my nutrient solution that the ph raises around 0.2 every 2 days using regular tap water bubbling constantly 24/7 and that I get a residue sat at the bottom of the bucket. Itâs not enough where I have to make a 2nd ph adjustment though but Iâd worry about using it with any system with small hoses as I think it would block any filters.
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i dont imagine they changed the buffering in V2.0 so we should be able to apply our findings to the new formula.
i have MC2.0 in route, so ill be able to play along with the new stuff.
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so the precipitant reactions are the same without the mes in regards to phâŚ
the sediment is tan, which rules out the mineral precipitation.
kelp meal is my new suspect.
oh how i love a good mystery.
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Good info. That seems like pretty mild change in PH to me. Over a couple a days with plants eating and such.
Would you say that your tap contains considerable amounts of carbonates or is high EC? Can I ask what you are using for PH down?
This does seem to be a recurring theme.
The precipitation that is shown above is likely different than the insoluble precipitate that folk have experienced. Possibly some sort of a slow reaction in the insoluble case. Sounds like another suite of things to try.
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Same in the sense that there is something starting to come out of solution around the PH of 7.5 and increasingly so as PH increases. Quantity and quality may be slightly different. I can see the instability in the PH reading as the precipitation starts.
I have been focusing on the buffer problem at the moment and havenât spent much effort playing with the precipitant side. So, I donât have much to say on that at the moment other than 7.5PH âseemsâ low.
Also, if you take a look at post #25, the precipitant is quite different. In that case, it appears mostly like mineral. Two differences, double the MES and using GH PH up.
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When exactly did Mega Crop go from 1.0 -> 2.0? Just curious which formulation I have on hand.
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