Fungus gnats and coco

Just hang some yellow stickies.....that should control them. If they do get out of control........3 drenches with Gnatrol will kill any larvae in the coco.
Fungus gnats are more of a nuisance than anything else.......the adult flyers pose no threat to the plant and the coco would have to be totally infested with larvae before you would notice a problem.

I only had a fungus gnat problem once when I first used my airpots.......after I covered them with pantyhose I never had a problem since.

The best thing I have found for fungus Gnats is a variation on the mosquito dunks with mosquito bits. They are made by the same company that makes the dunks, but its actually just BTI on ground up corn cob. I stir in 1-2 tbsp of the bits per gallon and let the water sit overnight before watering my plants. took about 2 weeks to be completely gnat free, but it works. After getting rid of the gnats i water once a week, or every other watering with the BTI water for preventative maintenance, and have had zero issues with gnats ever since.

Interestingly I've been having a chat with the guy from the Mosquito Bit company who literally just said the same thing. He says that putting the bits into a stocking and then into the water is a good way to wash the BTi and keep the water clean from the bits of cob.

EDIT: He did also say that it's fairly immediate when the bits hit water, so you probably don't need to leave overnight.