Calathea orbifolia brown edges!!! Why???!!
I'm sure your leaves have brown spots because they lack a little humidity and direct sunlight.
This plant is thriving! It might just be getting too much sunlight, so why not give it a new home in a slightly shadier spot?
I totally get it. I'm wondering if the main problem you're dealing with is due to two things: first, maybe you're not giving it enough moisture, and second, maybe you're using too many fertilizers. Let's start checking things out from these two perspectives and see what's going on.