I just had Sarcid flies/ fungus gnats they suck the problem isn't the flies its the larva that feed on the roots. I wound up with mine because i was keeping my soil to moist all the time. i think. Organicide at home depot is what Whiskytango recommended to me. used it and changed soil (when i re potted) that's how i got rid of them. But You need to look up pictures to see what kind of fly it was there are several others all of them are not really a good thing. if you don't see any more I wouldn't worry about it but take a close look at the fly and google "Cannabis pests" compare and it will tell you how to get rid of them.
quarteroy Reviewed by quarteroy on . CFL First Grow from Bagseed Complete Cabinet Cfl Grow Seeds: Regs Bagseed Soil: Botanicare Cocogro Nutes: FoxFarm Grow Big and Big Bloom Light: 9 26 watt CFLs equaling roughly 900 regular watts Ventilation: Intake Central Air Exaust 365 cfm inline fan Odor Control: none atm Closet/Cabinet: 34.5'x17.5'x71' Vegetation: Started on 24/0 but soon moved to 18/6 light cycle Rating: 5