In Bonsai we don't use a lot of organics as we want to control grow. Most people as organics (compost, peat, manure, etc.) per that type of tree's needs.
so here are two non-organic choices that you should be easily able to find:
Akadama is Japanese baked clay, specifically produced for bonsai and imported into the West; it is normally only available from bonsai nurseries and therefore difficult to locate. There are a number of grades of Akadama available including 'Double Redline' that is more costly but is of premium quality and less likely to break down.
Akadama is the soil of choice for many Japanese bonsai Masters and enthusiasts. This is partially due to its relatively low price in Japan where it is also easily obtainable.
Akadama can break down into a solid mush within 1 or 2 years.
Seramis/Turface/Oil-Dri are fired clays are readily available in the UK and US compared to Akadama and much cheaper. Fired clays are also stronger than Akadama and thus will not break down over time.
You could plant in either alone but, you would need root frets.
Or you could add some organics like a little pete, worm casings,powdered manure compost, or even yard dirt from a health piece of ground.
Look at my Tonxic Ten journal.
I would take 50% of my Bonsai soil and add organics, as my base. Then use the other 50% as a cap. I prefer adding lots of hornwort at start up to cycle. But, you could also do daily water changes for a week, them every 3 days, them weekly maint.
Either way with organics in the substrate NO water colum frets for a month. Excell would be O.K.
I don't run CO2 so I will not comment on it.