Good even weed Gloman, You ask where the dam gnats come form? Well they are a soil born fungus gnat. Larva in the soil you buy is the about the only place they come from in an indoor grow. they are a nuisance for sure and if they get bad enough the larva can really screw with the roots. Putting clean sand on top of the soil helps, they can't get through and diatomaceous earth work pretty good also. put on top of dry soil and it will cut the hell out the gnats as they come out. There are also some drenchs but I don't like doing that unless they are REALLY bad.