I looked at my bottle of mosquito bits - it's this one.
It has different instructions for mosquitoes and for fungus gnats: "May also be used to control Fungus Gnats. Sprinkle or spread the granules over the soil until the area is covered. Water will release the BTI into the soil where the larvae of the Fungus Gnats will feed on it and die. Repeat this process for a three week period for control. If Fungus Gnats reappear, repeat process for another three week period."
Apparently it's made of corncobs with a coating of Bti.
Fungus gnats... you will battle these for a while.
There a lot of things you can/have to do.
Drying the plant out- some plants can’t take it.
Cinnamon on top of soil- (antifungal) I heard it might be a particular kind.
Sand on top of the soil- hard to water
Mosquito bits- bits This had different outcomes for me. Bits tended to mold after a while if sprinkled on top.
I also added these small night bug light
I did all of these things.