If you have chemistry questions....

[squiggly]

that's SO awesome - so chelates are what keeps the ion neutral and allows it to pass through the casparian strip, as opposed to the plant having to synthesize a cation/anion to bond the ion and allow it to pass through the plant...correct?

Yup, it allows it to take the apoplastic route for uptake.

and in that regard ~ can you think of any chelates that the plant can readily use once it's been absorbed? I've been pretty convinced lately that if you can provide a stabilize rhizosphere and a standardized nutrient salt regimen, you would see very very good results with amendments of different acids and horomones in different stages to act as chelates.

I mean it's possible, but you'd have to know more about the metabolism of the plant.

and another question - do nutrient salts come to us already chelated? or are they actively being chelated either in the rhizosphere or by our plants?

Not if it's not labeled that way. Yes there is "natural chelation" that takes place and bacteria/fungi/roots all participate.

 

[caveman4.20]

Squiggly did you mention anything about chelates in flushing agents

 

[squiggly]

This thread is being un-stickied in favor of the CCC (now stickied)




If you have questioned unanswered in that document please forward them to my inbox and I will see that they are addressed there when time allows.

I have begun receiving a fair amount of PMs and I'm afraid I just can't keep up with them all. There are enough repeat questions that I feel a thread I can point people to would aid me in getting more help to more people.

That's what I'm all about, so this is my solution--please help me make it a success guys!

 

[ttystikk]

Hey, I have a chemistry question! Your explanation of ionic balance struck a chord with me, so please tell me how to balance things to support our little bennies?

 

[squiggly]

Hey, I have a chemistry question! Your explanation of ionic balance struck a chord with me, so please tell me how to balance things to support our little bennies?

I am working on a product to do exactly this and so must reserve the explanation for now. We can discuss this in private as I consider you a trustworthy friend--but it's not something I want to discuss publicly as none of what I'd do is likely to be patentable (so I must rely on proprietary formulation--much the same was as cap does with his packs).

If it does turn out that I can patent/protect my specific formula for this purpose then I'd be happy to share it with the farm at that time (I'm not a money grubber, and even if I were I realize that most products like these stem from the laziness factor rather than barrier to consumer creation).

 

[royfree2grow]

Hey Squiggly, I have a rather basic question (I think...): I've recently used citric acid (salt) to lower my water PH level and I noticed that the PH level varies from the beginning to the end of the watering (irrigation); I start of with 6.5 (after the citric acid) but when I check the water leftovers I get PH of 6.6-6.8. I've never checked it this way before but it also happens with a phosphoric acid based product I'm using although the variation is smaller. Do you know what's going on here? more specifically; what can cause this PH variation?

 

[urbanfog]

Sqiggly is the authority, but from what I read the citric acid will swing ph. I have heard a better choice if no other options is a solution of battery acid and water. Personally I use the granular ph down, but may go to the BA after my big ass bag of ph down is gone. Cheap to make, easy to get at the auto parts store

 

[ttystikk]

There's nothing wrong with citric acid. Just keep in mind that there are two kinds of acids out there; strong acids and weak ones. Phosphoric acid is a strong acid, hence a little goes a long way. Citric acid is a weak acid, so it takes more to do the same job of lowering pH.

However, this is far from the whole story! It turns out that weak acids do a better job of buffering, and they have roles to play in plant nutrition that strong acids do not. I use the dry pH down from botanicare and I'm pretty happy with its performance.

True, you have to watch your pH a bit more, but once you have it set it is more stable.

 

[squiggly]

Citric acid and phosphoric acid are both triprotic acids which means they can lose a total of three protons to solution. This is different from an acid like HCl which fully ionizes in solution.

 

[ttystikk]

Citric acid and phosphoric acid are both triprotic acids which means they can lose a total of three protons to solution. This is different from an acid like HCl which fully ionizes in solution.

And without a trace of sarcasm, because I really want to know- how does triprotic action in acids help our hinder our quest for pH balance and best growing practices?

 

[squiggly]

And without a trace of sarcasm, because I really want to know- how does triprotic action in acids help our hinder our quest for pH balance and best growing practices?

They basically act as their own buffer within their various pH ranges (which correspond to the pKa's of each of the protons).

So the acids donate protons in a stepwise fashion. IE the "first" proton of ALL of the molecules will come off first--and then the second, then the third. That is why the graph above looks like a staircase.

This is a graph of a solution of phosphoric acid which is having a solution of NaOH (neutralizing agent) slowly added to it. The rapid upswings in pH correlate to the points at which all of the first/second/third protons have been neutralized (abstracted).

Each of these protons has its own pKa value, and this graph shows essentially what that means.

 

[dizzlekush]

Squiggly, which basic available horticultural pH adjusters will provide the best buffering capacity to the solution? (i.e. buffering differences between acids of citrate, phosphate, sulfate, nitrate and K/Na salts of bi/carbonate, silicate, hydroxide etc.)

Am I correct in my assumption that different forms of Phosphoric acid have the same effects on pH once in solution, such as the difference between 70% aqueous phosphoric acid and PeKAcid (essentially 1 part MPK to 2 parts white phosphorus)?

I've been made to believe that the Phosphate/Carbonate combination is the best for buffering, but don't know with any certainty.

 

[squiggly]

Squiggly, which basic available horticultural pH adjusters will provide the best buffering capacity to the solution? (i.e. buffering differences between acids of citrate, phosphate, sulfate, nitrate and K/Na salts of bi/carbonate, silicate, hydroxide etc.)

Am I correct in my assumption that different forms of Phosphoric acid have the same effects on pH once in solution, such as the difference between 70% aqueous phosphoric acid and PeKAcid (essentially 1 part MPK to 2 parts white phosphorus)?

I've been made to believe that the Phosphate/Carbonate combination is the best for buffering, but don't know with any certainty.

It depends what pH you are shooting for. Buffers typically split the difference between the pKas of their substituent parts.

So an acid with pKa of 10 and an acid with pKa of 5 will produce a buffer @ 7.5. Take that with a grain of salt.

Thermodynamics of acid/base solutions and all of the requisite calculations take up a few months of undergraduate chemistry education, I don't think it's really something I can do justice here.

Buffering capacity is a function of how much of the buffer you have in solution. If you have more it will take longer to deplete. So the question isn't which buffer has higher capacity so much as which buffer holds the pH you want and the plants can handle the most of in solution without getting pissed off.

 

[dizzlekush]

So which buffer combination in your opinion would keep pH between 5.5-6.5, that is also relatively non-phytotoxic so you could use significant amounts of the buffers combined constituents?

Am I correct in my assumption that different forms of Phosphoric acid have the same effects on pH once in solution, such as the difference between 70% aqueous phosphoric acid and PeKAcid (essentially 1 part MPK to 2 parts white phosphorus)?

thanks,
dizzle

 

[squiggly]

So which buffer combination in your opinion would keep pH between 5.5-6.5, that is also relatively non-phytotoxic so you could use significant amounts of the buffers combined constituents?

Am I correct in my assumption that different forms of Phosphoric acid have the same effects on pH once in solution, such as the difference between 70% aqueous phosphoric acid and PeKAcid (essentially 1 part MPK to 2 parts white phosphorus)?

thanks,
dizzle

Probably a carbonate/phosphate buffer to be honest--recognizing that carbonate is more important and effective than the phosphate, but pH drift will be less dramatic with a bit of phosphate around.

 

[dizzlekush]

Probably a carbonate/phosphate buffer to be honest--recognizing that carbonate is more important and effective than the phosphate, but pH drift will be less dramatic with a bit of phosphate around.

Very much how it was put where i read it, with emphasis on carbonate.. The author (Daniel Fernandez, maker of Hydrobuddy) said that the cutoff for Carbonate was ~100 mg/l (ppm) at the pH range we're shooting for since above 100 mg/l, at the desired pH range, the levels of hydrogen carbonate are likely to reach phytotoxic levels.
http://scienceinhydroponics.com/201...oponics-what-is-the-best-cheapest-buffer.html

 

[squiggly]

Very much how it was put where i read it, with emphasis on carbonate.. The author (Daniel Fernandez, maker of Hydrobuddy) said that the cutoff for Carbonate was ~100 mg/l (ppm) at the pH range we're shooting for since above 100 mg/l, at the desired pH range, the levels of hydrogen carbonate are likely to reach phytotoxic levels.
http://scienceinhydroponics.com/201...oponics-what-is-the-best-cheapest-buffer.html

Seems legit.

There's gotta be something better, but if there is I'll probably market it and sell it tbh :)

 

[dizzlekush]

Well there's Amberlite ion-exchange resins (e.g. IRC-50, DP-1) and MES. Also whatever is in pH perfect unless that's MES also.

 

[squiggly]

Well there's Amberlite ion-exchange resins and MES but that only really has value for recirculating hydroponics. Also whatever is in pH perfect unless that's MES also.

I'm currently developing a premade buffer/feed delivery system for brewing bennies--when I'm done with that I may look into developing one for hydro, but I imagine AN probably has that shit thoroughly patented, we'l see.

 

[dizzlekush]

I think i was incorrect by saying those were only for hydro. I just think you test to get the best usage of them in hydro.