“The 100% cure for fungus gnats is circulation. You don't have to do anything except circulate air over the tops and bottoms of your pots. If you have holes in the sides of your pot, get them circulated as well. Don't give adults a chance to land and lay. You will have the larvae in the soil go adult and get blown away.â€
That’s good advice. I had a few gnats and adding fans that blow across pots 24/7 Got rid of them. As I was advised here, if they can’t fly and land on the soil they can’t lay eggs.