Is this due to magnesium or nitrogen ?

Hello, I have 4 White Widow plant and all of them seem to have the same problem.
I use an indoor setup.
The lower leaves are becoming yellow (but not falling, at least for the moment), and that since one week.
I water them every two days, approximately 250ml per plant.
I have a nutiment solution (5- 4.5 - 3.5) that I mixed with the soil at the very beginning (4 weeks ago).
Yesterday I noticed something new on one of the plant, a little yellow round in the middle of ONE leaf !
The light is a 250w HPS and is +-40cm far from the cannopy so I don't think it due to light burn.
They are still in veg and are 25cm tall in 5 weeks (from seeds) which is not really great I think.

Could you help me please ?
Here is some pictures :



Edit: The fertilizer I used is http://en.jungleboost.ch/organic-dry-fertilizer.html

bad ph or too much N?

lunkwill said:

Hello, I have 4 White Widow plant and all of them seem to have the same problem.
I use an indoor setup.
The lower leaves are becoming yellow (but not falling, at least for the moment), and that since one week.
I water them every two days, approximately 250ml per plant.
I have a nutiment solution (5- 4.5 - 3.5) that I mixed with the soil at the very beginning (4 weeks ago).
Yesterday I noticed something new on one of the plant, a little yellow round in the middle of ONE leaf !
The light is a 250w HPS and is +-40cm far from the cannopy so I don't think it due to light burn.
They are still in veg and are 25cm tall in 5 weeks (from seeds) which is not really great I think.

Could you help me please ?
Here is some pictures :

View attachment 3279700 View attachment 3279701

Click to expand...

I am having the same issue as you are my friend. Its been two days since I've added GH Cal-mag. My PH in soil is around 6.8. It looks to be turning green again, but very slowly.

Thank you for yours answers.
I currently have no PH test I'll try to buy one the weekend what's GH Cal-Mag ?