I use the yellow sticky traps and just recently gotten this mosquito trap that works for the fungus gnats.
I agree with the other post that MiracleGro potting mix may be part of your problem. I stopped using it because it seems to hold onto moisture too long.
Also, your fungus gnat problem may be seasonal. It is for me. In winter I never see them.
I can't find the exact kind that I bought two years ago. If you search "UV insect trap" on Amazon you can find the best one for you.
This one is similar to the one I bought: