Is it wee gnats you have ?I get them all the time wee fukz. Window open in they come. Or in soil bags as eggs. Pain in the tits.
Aye m8 that's them. This soil I think has them in but I couldn't get the usual stuff so had to go with it. No idea how I went 7/8 years growing without seeing one now I can't shake the wee fkrs!!