Planted Tank Guru
Join Date: Mar 2009
Location: Madison, Wisconsin
Hi Adeeb. It's good to see you here.
Thrips are almost impossible to kill. If they have killed off or damaged many of the plants the easiest thing to do would be just pitch everything that is still left, carefully clean up and start over with new plants.
You could try a CO2 bomb for thrips, but that will probably only get the adults, not the eggs.