Colleen from Fond Du Lac writes
You will usually see drain flies developing in a toilet only if the toilet is not used very often. InVade Bio Drain probably won't be the best product to use in your situation. You can turn the water off to the toilet and flush it so that the bowl and the tank are empty. Thoroughly scrub both, paying special attention to the area under the lip of the bowl and the tank. Scrubbing and cleaning these areas will help eliminate the decaying organic matter that these flies need to breed and develop. While the toilet is drained you can apply Invade Hot Shot Foam to the tank and the bowl and let it sit overnight to clean all of the cracks and crevices that you may not be able to clean properly. Invade Hot Shot would be a good choice because it will expand to cover all of the surfaces you need to treat. This may need to be repeated a few times before you get rid of all of the gunk that can build up over time. All drains in the infested room should be treated with either Invade Hot Shot or with Drain Gel.
Answer last updated on: 09/21/2017
