My indoor enclosure for my Russian tort is now teaming with fungus gnats. The substrate (coconut coir and cypress mulch) is only about two months old and I mist it a couple times a week to keep it from drying out. I'm going to stop misting and let it dry out under the lights, but is there anything else I can use? I have imidacloprid granules I use for my house plants. I've heard it's "pet safe" but I'm reluctant to use chemicals in my tort's completely natural indoor winter home. I don't want my tort to have to share his home with pesky gnats!