Got @gnats ?
Fungus Gnat soil treatment - Gnatty Dread
1 gal dechlorinated, warm water
1 tsp molasses
1.5 cup ‘Mosquito Bits’
Combine in gallon jug & shake vigorously several times over 24-36hrs, keep unsealed in room-temp., dark.
Filter out mosquito bits with sieve(use outdoors or on houseplants)
Mix resulting brown STINKY funk with water 1:1, apply to soil surface thoroughly after normal watering or between waterings.
This is done in addition to light soil surface covering/mulch with the Bits.
I did this and went from Gnat-city to almost zero Gnat-tivity in just a few days. DRASTIC DIE-OFF. I 
love it.
My previous application of just the Bits themselves has required 3x as much time at least(typically see same results after 2 weeks).
c.s