They also have a bag you fill up with water and it attracts the flies, once they go in they can't get back out. Just put it in an area where they are and you'll notice a reduction. I got the bag at Home Depot .
Misty- Samoyed Mix, Tannor- Golden Retriever CGC
Robyn- GSD CGC, TC, Midnite-GSD CGC,TC, Brennan-Golden Retriever CGC, Batman-Husky/Greyhound , Apollo-GSD