Unable to visit grow regularly this week and had issue with Nat fly again. Done some research and found Diatomaceous earth. Works a treat! Couldn’t believe the results. I did purchase a overly priced version from hydro store close by just as I needed the same day. But this shit really is amazing. One dressing done the job and washed through after 2/3 waterings. I was hoping to having to only dress once as plants going into flower and that’s all it needed. Not one Nat fly in the room! Unbelievable.