Can't you just put a little spinosad in your water? That should kill them and since it is systemic it should protect the leaves too. It is also organic. I use about 5-10 ml per gallon a few feedings and that seems to hold the bugs back, but there is no recommended dosage. I got the idea of feeding it because of a study with rockwool, tomatoes, and spidermites. There are also plenty of people that use it as a drench. You could also use mosquito dunks, but the spinosad will kill 'em all.
I believe folks have tried spinosad on root aphids and it did not work. Also mosquito dunks only piss them off. At this point the only thing folks are saying completely works is this met52. Everything else seems to reduce their numbers but they stick around until the time is right and then crush harvests.