Hi neighbors, Many of my 10+ houseplants are infested with pesky fungus gnats. Does anyone have any left over Gnatrol or Knock-out Gnats (or any other biological insecticide containing Bacillus thuringiensis--BTi)? I thought I'd check with all my fellow gardeners before shelling out $25 for an enormous amount of the stuff! If I end up buying it, I'm happy to share with anyone else who has overwatered their poor plants. Thanks, Laura