Having some problems with my plants :(

[420xVita]

Hello, let me start off with some info.
I have 2 Big bang autos and they are about 30 days old.
So i gave them 4 ml and i should have given them 0.4, this only happend once like 4 days ago and the leaves are starting to die of (lower ones) i dont know what i should do i started flushing them but doesnt seem to work is it a nute burn or am i doing something wrong?

 

[Mike Wright]

Hi 420xVita. How did you flush them? Did you run 2-3 times the volume of the pot size of water through them?

 

[420xVita]

I used twice the volume with tap water and i dont see why they are still dying out, btw they are starting to show signs of flowering at least one good thing