Akadama is a clay granulate and particularly suitable for bonsai. This soil provides good moisture in the pot, has a neutral pH and does not contain too many nutrients.
This earth 100% can be applied or mixed with potting soil to 50%. Bonsai should always lightly fertilize for a healthy growth.
If you repot the bonsai can prune up to 30% of the roots.
For proper regeneration of the roots, you can shorten the process only the older thicker roots.