Thank you for the reading material! It really helped.
I learned the answers to my earlier questions:
#A1: One-third of the water needs to be changed.
#A2: The instructions for cycling tanks are the same for pre-established tanks. Water is changed daily in the first week, and every 2-3 days in the second week and onward. Then after a month has passed, the water is changed once a week.
This is a really great guide, it even has a list of all the rock types (I'd been looking for that and hadn't found any). Read and bookmarked.
And now I have more questions (sorry!).
This is my first time learning about ADA Power Sand and Powder Type. Sadly it's too late for me to use Power Sand, as I've already added the aqua soil to the tank.
As for Power Type, I do want to support the roots of my plants better and the aquasoil pellets are pretty thick. I read that if you use Aqua Soil Amazonia Powder, to not use as much Normal type aqua soil. However, I've already put in ADA Aqua Soil. Would it work out if I still tried to top it with the powder?--To fill the gaps between the pellets and plant plants easier.