Fungal gnats and other issues

[littleflower]

Getting discouraged! First, I just realized that I have a fungal gnats, I believe in several of my orchids. i’m going to try the mosquito dunk, but I am concerned about my media. Most of my orchids are in miracle Gro orchid coarse mix, but I wonder if I would do better with something else. I actually have a Vanda in charcoal, wonder about using that for other orchids. Also, several of my plants have roots that are splitting, and then there’s the leaf below. Any help would be greatly appreciated!