hey,, I think I know the bugs you talk of,,when the MG soil has been wet for a prolonged period these bugs appear,, what I did was put a small trough or tray(I used the fat tray off a G.Forman) with water in it,,and place it inbetween the pots and then allowed the pots to dry out ,almost too much, and the bugs launch themsleves into the water. Then or before drop one drop of bleach or anything like that in the water trough/tray and that kills the wee bugs,,that way you dont have to add somthing that going to kill the good stuff in that MG(there stuffs okay as long as you know how to use it). I grow in it and know the white bugs you talk of,,
So if your letting the soil dry out every moring give your plants a good misting/shower to keep them hydrated and as the soil drys out the bugs will die back.
Yeah also whats your watering routine????? as I found it was me that was watering to much and the worms seem to 'activate' in the soil,,so yeah let the soil dry up and they should start to die back.
Anyhow good luck and take it easy....