@celestia you can find it on Amazon. Thatβs where I get mine. This is what it looks like. You can see my alocasia is growing a root out the top lol. You can also try Leca too. Some people really like it.
Mine started doing the same thing when I first brought it home. The game changer was the humidity. The leaves stopped turning brown after I moved it from a spot with 30-40% humidity to a cabinet that I keep around 50-70%. Hope this helps, good luck!