Red_Snow:So far, I never see any of the bathroom fly anymore in my toilet. Still pouring hot water every few days. But still see lots of black worm coming out whenever I pour hot water (they hide near the drainage). Just wondering, where actually the worm come from? :?Now I am using Mr.Muscle drain declogger fortnightly. Pour 1/2 of the bottle, followed the instructions on the bottle. So far, I hv not seen these flies at all.In the past I also poured boiling hot water into the drains. It did not help much. I guess the eggs were on the sides of the drains. So I used the shower hot water to spray at the sides. Less fly after that.