Having read what this forum and every other place has to say, and realized that nobody with any credentials agrees with me that dirt is dirt, I concede and am going to repot using a standard akadama, etc., mix. A question:

One of my reasons for hesitating is that the climate here can be very hot for weeks and I cannot always water every day. Somebody else in a hot climate (Clicio?) - what mix of organics do you use? Do you do anything outside of the akadama/lava/pumice basic mix to keep the trees hydrated? I need to accommodate the vacation time issue that the kid who waters may come by anytime of the day, so the soil mix needs to stay hydrated from morning today to afternoon tomorrow.

I hope I can help.
Organics are 20% to 40% of my mixes, as pots can get dry in a matter of hours here; so yes, organics hold more moisture.
Conifers get less percentage and tropicals more. Jaboticabas and Barbados Cherry love wet feet.
My usual mix is crushed brick, akadama, coarse sand, kitty's litter and organics: pine bark+coal+black nursery soil.
It works, here.

I don't think u can have a mix, that allows you not to water every day if you live in hot climate. You can add water-retention by adding organics, akadama, Diatomaceous Earth etc - that can help you when there is hot, but what when weather gets colder, and if you get a rainspell for a few days.. then your soil will stay too wet, and you destroy the oxygen / water balance which can have bad consequences for the roots.
Ppl only focuses on the soilmix to get it right and stuff like that, but by moving your bonsai to a less sun/windexposed spot can help aswell against water evaporation

Alternatively you should consider using a less water retentive mix + automatic watering system?

My mix:

What are the green rocks?

My eye looks at a tree and expects to see dirt in the pot. This will be a good training exercise for me.

I spent an hour mixing things together and repotted two of the indoors tropicals, and used up the hour's worth of mixing. Getting ready for spring is going to take some time this winter. But, after two days they haven't dried out so I guess I was overly concerned. Does pumice hold water the way the organics do?

i live in very hot weather with 105*f+ for weeks at a time. unfortunately there is not way around it. i have to water up to twice a day sometimes.
i switch a couple trees to an organic mix that consist of Turface Calcined Clay, Peat Moss, Pumice, Small Fir Bark, Vermiculite, Sand but with the heat it almost makes no difference. downside is in winter im afraid my soil stays too wet and risk root rot on those trees.

"GREEN STUFF" is Basecote, slow release fert.
Yes, there is plenty of black soil in the mix. I keep a drier layer on top to check visually if it needs watering.
Yes, I still have to water twice a day in the summer, and once every two days in the winter (average; I NEVER water them.on schedule).

Dirt? Nothing grows in dirt. Akadama is not dirt. Soil is not dirt. The soil mix you use is down to you, if you are in a hot area then you may need a mix that holds more moisture, in a cooler climate it may be that less moisture hold is needed. Whatever works for you is what you need.

Did you see this article of mine, talking about substrate?

www.growingbonsai.net/characteristics-of-good-bonsai-substrate/

I hadn't seen it, and it is all good stuff. Thanks. I had searched a couple of different phrases, but didn't think about substrate.

I am faced with an issue, which is what to do while we are out of town. I have been paying a young man in the neighborhood to come by once a day, water the trees, and feed the fish. He can't tell from blocks away if the trees need watering. Maybe I'll just double the pay per day. My Scottish ancestry rebels. The rest of the hot season I can water more than once. The travel days are the issue.

Being the numerical person I am what I have really wanted is very specific directions, for tree A, x cups of this, y cups of that, etc., all directed at the climate in my backyard. I guess that is unrealistic.