SWIM has got a large amount (~800g) of MHRB on the way and needs a quick and effective way to extract it. SWIM has done small STB extractions before but FASA sounds much better due to simplicity and speed.

SWIM has found 2 teks that look good but has a few questions:

Citric Acid Tek

Calcium Hydroxide Tek

The citric acid tek seems to be extremely simple, yet it doesn't seem to be very widely used, are there any serious disadvantages to it?

While one tek might not be 'better' than the other, how do they compare to each other (like in terms of purity, effectiveness, speed or any other pros and cons)?

The Calcium Hydroxide tek doesn't mention several ratios:
In step 1, does 1 part mean by grams or by volume?
In step 4, how much acetone is required per gram of MHRB?
In step 5, does it mean add Fumaric acid directly to the freebase solution, or does it mean to prepare a new solution? If a new solution is required, how much FASA is required per gram of MHRB?
In step 7, again, does 1 part mean volume or mass or what?

Sorry thats a lot of questions, but SWIM has looked at great length and found no answers. Thanks in advance.

For SWIM, the acetone/citric acid FASA tech yielded some results, but it was not at all the yield expected, and SWIM was unable to find very much supporting documentation on the forum to help SWIM along the way.

SWIM decided then to pick up some cheap xylene, and because SWIM had followed the STB tech previously using NaOH and Naptha(the stinky reason SWIM decided to look for another tech), he felt more comfortable following basically the same STB directions using xylene, and then instead of freeze precipitating the solvent, he prepared a FASA solution and added it to the xylene. This time SWIM immediately saw clouds forming from the xylene/FASA solution.

Initially SWIM was impatient and shook the jar vigorously, causing the clouds to settle, and a powdery substance to accumulate on the bottom of the jar. This yielded active spice, but in following trials, SWIM became aware that by not shaking or even disturbing the jar after adding the FASA, very nice needle-shaped crystals formed on the sides and the bottom of the jar. Make sure to wait until the xylene/FASA solution is clear and un-cloudy(it will start at the top of the jar, and slowly over the course of a day or so, the line between clear and cloudy will move down the jar to the very bottom)

SWIM would suggest breaking your bark into 100 gram trials, and attempting as many different variations on the FASA tech as you can with the bark.

Though this method of using xylene was far less stinky than the Naptha STB method (because there was no need to evap the solvent), it still gave SWIM a bad feeling every time he had to crack open the jars. Because of this, SWIM would like to investigate limonene techs, and possibly even FASA with limonene(from the forums there seems to be some level of success in this area, but not a clear understanding of the ratios used to ensure a fairly pure product). SWIM has tried both freebase and oral methods, and has found that he doesn't really enjoy the freebase method, and the oral method has been amazing, and so thinks settling with a hygroscopic salt form like acetate or maybe citrate would be acceptable in his eyes.

Oh, and the speed of the xylene STB to FASA method is about 2 days until product is yielded. The yield with SWIM's first attempt, doing about 4 different pulls, was between .8% and 1%, which SWIM feels could be higher after all that he has learned from the first trial.

The most helpful resource for SWIM was the new guide on the wiki.

SWIM has yielded .8 to 1.3 using STB/xylene/FASA. Leaving the Xylene/FASA solution to settle for 3 days before carefully decanting. But this will include n-oxides and other alkaloids.

However he only uses this spice for pharmahuasca.

In his experience if he wants freebase crystals he goes A/B then pulling with a weaker solvent, freeze precip, then room temp xtalisation.

But he then adds xylene to the original solution, pulls with xylene, adds FASA then adds the precipitants to his DMT Fumerate collection.

Another reason for this is he "thinks" the freebase required through Fumerate to Base conversions is lacking something that his straight pull solvent has. However this could just be a lack of oils left out in the FASA step and some people prefer that "cleaner" spice.

For FASA I think the general opinion at this time is that limonene is not the best substance.

I really want to try the CASA -> FASA tek due to its mechanical simplicity and scalability, but like in the OP, I don't see too many people giving it a shot, and am curious as to specifically why?

I understand the documentation is lacking, but members of this forum seem dedicated to experimentation.

I know some Nexus vets say they have tried it with some issue, where did these issues arise? Where is yield being lost? This tek is so simple (with the exception of keeping water out), that the only step I could imagine there being a loss of yield is right at the beginning, with not enough DMT being converted to citrate, or not enough citrate dissolving in the acetone. Either way this form of yield loss is one of the easiest to overcome.

Does the MHRB + CASA solution need to be strongly agitated, or weekly agitated? Is heat that important?

I don't expect anyone to have these answers, I'm more than ready to find them out myself, but of course anything that has been answered already would help me save some effort later on.

One last question: why does the tek in the sticky thread state that the pKa of fumaric acid is higher than citric's? Fumaric has a pKa of 3.03, but the tek says it is 3.44 (or something) and thus weaker than citric!