First thing I tried was a product from grow shop called Gnat Off - didn't work and v.expensive considering. Have tried the stick pads and got quite a lot of them, have them up on the ceiling and will carry on. They must be living off something, how much damage do they do? Are they a serious problem? Should I just use that systemic pesticide stuff and say goodbye for good?
BTW while on the subject of coco, I use cannazym and reuse the pots. this is 3rd time round, how many times can you reuse the coco with zym b4 you have to replace it?