Been a long time viewer but as i don't speak or read Japanese.. i don't understand which substrate you used or what you added to it... If you could please share the names in English that would be helpful!
Thank you for watching. Kind of water plant is "Bacopa caroliniana". The rock used for the layout is lava. The soil used is horticultural soil. Use large and small grains separately. I am not good at English, so I am translating it.