Help - Leaves Losing Color and Yellowing

[TJGrow]

I have some OG Kush plants that have turned from dark green to light green and then yellow.

They were a nice dark green while vegging and into the first 10 days or so of the flowering period. Then over the next 10 days or so *all* the leaves started to fade in color. It took time for me to spot it as the change was slow at first.
I increased the air flow and raised the lights which dropped the temps from 85-90 down to 82-86 and slowed down the nutes. Now most of the new growth seems to have come in a nice dark green.
My trouble is that I'm still seeing leaves pale and die. It seems to start on the edges and tips in that the centers hold the color a little longer. Its not a burn as the leaves seem unchanged except the color.
Is this type of damage a heat/ventilation issue or a nute issue?

These pics are OG Lemon Kush at 43 days flowering time:

 

[eBUD]

Try keeping the temps where you have them. Plants wont take up water/nutes if they aren`t transpiring moisture. Meaning if its too hot or too cold the plant is stressed and will not feed leading to deficiencies and possibly death. Also i have seen a few cases of the leaves yellowing and "bleaching" due to 1000w HID lights being too close. Its rare bc usually the plants would just burn but if your fans keep them cool you can bleach a plant.
By the way what nutes and at what strenght are you using them? In what system? Whats your Ph? Hope the growth keeps on coming Dark Green for you bro. Let us know how it`s going.

 

[TJGrow]

Thanks for the feed back. I think I got them too hot/too close to the light and once the leaves started to bleach the yellow was inevitable. I did move them back from the 1000w or a set the light to 750w. My Ph is 5.8 and I'm on simple recipes of General Hydroponics nutes. I was mixing a 10gal recipe into 12 gal of water but I backed off to a 3 gal recipe in 12 gallons. I have been flushing with Ph water regularly and they have been on that for the last few days. I run a feed line from the next room so I have to flush that regularly.

I put up a Journal at: TJGrow Journal

 

[BluDreamZ]

I have the same problem everytime I switch to my 1k hps.... yet to solve the problem.

 

[Buaxadruax]

check your root zone. You may have fungus gnat larvea burrowing into the lower portion of the stem. This will cause a slow progressive yellowing.

The other fella mentioned light bleaching. When I switched from 600ws to 1000ws I noticed this became a issue.


Do you flush the root zone biweekly with fresh water?