Thanks, Janice, for sharing your experience with the Zevo Flying Insect Trap Refill Cartridges. Yes, having reduced lights in the area of the Trap as much as possible definitely helps, but the Trap will lure in flies, gnats, and fruit flies anytime, as long as bugs can see the blue and UV light. Take care that nothing's physically blocking the light. If you'd like more help with this purchase, we're here to assist Mondays through Fridays, 9 AM to 6 PM, EST. Our phone number is 1 (800) 374-9429.