Leaf yellow

Hi, have a few girl yellowing, at first thought it was Cal mag issue. But seem to be geting worse. Any advice ?
Did have a fugnus gnat problem before but I hit every plant with merti 75 and a doctor doom for the room.

Thanks

Little info


1 week flower
Med Hugo 6by6
Nutrients ppm 1000-1200
5.8-6.2 pH
R o water
GH 3 Part

Have you used the cal/mag? if so how often? When did you last see a fungus gnat. One if not both of them are likely issue(s) you should deal with.

Take a look here: http://www.growweedeasy.com/calcium-deficiency-cannabis

and here:

http://www.growweedeasy.com/fungus-gnats#fungus-gnat-damage-leaves

Good Luck and Great Growz

Oh, I forgot to add this: http://www.growweedeasy.com/magnesium-deficiency-cannabis

And that was the point to your question I believe.

I think your correct , pest causing deficiency signs. just found a few I think. It pretty big flyer though here a pic. I dont know if its a gnat guess run merti 75 for abit.I cant shake this gnat problem. merti75 don't seem to be stoping them.

get some of this:

Thanks I will check it out.