Pale plant in flower!

[oilman5150]

Could someone please advise me what issue i'm having so I can try fix it today?

I'm growing Brian Berry Cough in soil with perilite mixed in in a 5 gallon pot.
Nutrients are Botanicare. Microbials = Mammoth P. Terpinator being used as well. Mix is always around 6.5 pH.
Just flipped to flower 4 weeks ago and she is just getting pale on all of the larger fan leaves. This plant is about 4.5 feet tall and NOT bright yellow but lighter green with a little yellowing and green veins at first but yellowing as it progresses. The plant is under the center of the light so it is definitely getting enough light under 1000watt HPS light. It is on a regular feeding schedule, no over watering, no pests, the ladies get thoroughly inspected on a daily basis and this lighter color started appearing in the last 3 days. Its time to feed again today and I could use some professional help on this please.
Let me know if you need more info. I pulled this leaf off and attached a picture so you could see it out in regular lighting to really get an idea of how it looks. This one has the yellowing going on a little more than the others.

 

[oilman5150]

The veins are yellowing as well as the leaves and The plant is getting lighter in color despite being watered yesterday. I really want to do right by this plant. Please help!

 

[macdiesel]

After feeding your plant for a long time in the same pot, you'll start to get salt and nutrient build-up. Measure your ph coming out of the bottom of the pot to see where it's at. Then flush the pot with properly ph'd water, and then feed again with proper ph'd mixture.

 

[Ratzilla]

Hello
I bet your hoping somebody responds Hu?
Being your around 3 weeks in flower I would give it another normal vegetative feed.
When I look at your picture I think I see a touch of a K deficiency.
Being potassium is responsible for much transpiration within the plant make sure your feed has that base covered.
Also where that pictured leaf came from on your plant can help in determining what deficiency maybe happening.
You know mobile and immobile elements.
Leaves of mobile elements will show on the bottom of the plant first and immobile elements will show on tops of plants first.
You say the whole plant looks like it is fading to a light green?
That makes me think a N deficiency?
In not knowing your strain and your practices in growing it is hard to help you much more.
Maybe my post will jar other members to give their views.
Wishing that I could help you more!
Ratz

 

[oilman5150]

Thank you much guys! I was planning on flushing it today because I figured it was probably a lockout as opposed to an actual deficiency. I will try to get a few more pictures right after the lights go off so that you can get a better idea of what I'm seeing.

 

[WilliametteWilly]

It kind of looks like overwatering. The way the tips are curling and yellowing is a sign of nutrient burn. Leaves also yellow as the plant flowers and nitrients are pulled from the leaves for the buds. How many weeks to harvest? What strain?

 

[oilman5150]

Strain is Brian Berry Cough.

 

[oilman5150]

Anyone see anything different when looking at the additional pics?