Sorry to be the bearer of bad news, but 'no pest strips' will not get rid of fungus gnats, at least not the variety I have here. I'm in a cge environment, meaning The no pest strips can actually build up in there, but it will not get rid of fungus gnats. I use mosquito dunks for the gnats. I put it in a nylon sock, crumble it up and submerge it in my res. In your case you can crumble it up a bit and mix it with your feed water and sprinkle some of the dry mosquito dunk over your soil.
The no pest strips work (should work) for spider mites, if they don't you are venting to much for the product concentration to increase in your grow space.
Good luck!
Kind