On a fungus gnat infestation that is that bad, your going to have to bust out the nukes on them...
1. Remove plants from room and clean entire room with bleach water
2. Buy some Gnatrol, I only use this with bad infestations, it will kill all larve in the soil
3. Buy some Fox Farm Dont bug me spray, or some other type of pyrithrum spray
4. Change your fly strips more often
Also do a daily check on your D.E. layer on top of soil and pat down any cracks that a gnat can fit through
1. Remove plants from room and clean entire room with bleach water
2. Buy some Gnatrol, I only use this with bad infestations, it will kill all larve in the soil
3. Buy some Fox Farm Dont bug me spray, or some other type of pyrithrum spray
4. Change your fly strips more often
Also do a daily check on your D.E. layer on top of soil and pat down any cracks that a gnat can fit through