Bjorn. Where do you source your customizable Aoki?
All sources on line have different premixed ratios ( some not even contain lava rock or pumice) and certainly not particle size.   I live on the east coast (Boston area) so our weather is a mixed bag.  I would love to just be able to order this premixed with correct particle size.   I also have no problem sourcing all the materials and mixing myself, but again, no particle size options.  What vendors/merchants do you use/recommend???

Hi! Bjorn answered you on the course as well, but to be sure:
From my understanding, customizable blends are usually reserved for massive wholesale orders, not for individual buyers. Bjorn
www.bonsaiempire.com/courses/intermediate-course-3/03

Oscar,

Thank you very much.  I have not seen a reply in the forums until now.  Nor  have i seen one listed in the course comments, only 1 comment asked by Razvan and answered by you..  Nothing else shows up.  I am not able to see what it is you are telling me is there, Just an FYI.
Again, Thank you so much for your assistance. I really do appreciate it.

I used to take the 1/3 - 1/3 - 1/3 ratios very seriously and measure out exact amounts, carefully filling a measuring cup up to exactly level, and so forth. Then carefully stir to get a very even mixture.

I saw a video of a Japanese bonsai expert in England demonstrating repotting. He had three wheelbarrow of akadama, lava rocks, and pumice and he had a large plastic container. He took two large double handfuls of each, dumped them in the plastic container,  stirred his hands around three or four times, and proceeded. 

What wound up in the pot was probably 30% to 40% of each component, not necessarily evenly distributed, and if that is good enough for an expert, that's good for me. Now I spend much less time mixing.

In fact, what I do now is sift all of last year's repotting left overs, guess it is about a third baked clay, pumice, and lava, repot the tree, dump a bunch of coffee grinds on top, and use a chopstick or something pointed to poke the stuff around the roots, and wind up with a lot of all four components in the pot. The trees are all healthy and I have to pinch them back all summer, so it must work.