Two Tone...not an option I ordered

My WW plant is starting its 4th week of flowering. The plant grew very fast and nearly a foot in the first week of flowering and eventually got within an inch of my 400W HPS lamp by the end of the second week.. It wasnt that hot as I have a fan blowing through it but it nearly touched the lamp so I raised the lamp up 2 feet. The upper sets of leaves were yellow (? I am colorblind) and so I dosed them with a full strength of FF BB and TB (usually use a fourth of a dose every other watering. I water 2 times a week). The leaves started to turn green after feeding but seemed to have stopped. I dont know if it was the light that caused this or lack of water or lack of nutes but I dont want to do anything else until I get some input on what might be happening. Can anyone look at my pics and offer some suggestions. I just watered today w/no nutes as usual. Thanks.

Specific grow info:
Temp. day -75-80degrees
night- 70 degrees
pH 6.0-6.4 consistently measured
Humidity at 35-40%
400W HPS
Nutrients FF Big Bloom and Tiger Bloom at start of flowering and also a few drops of VF-11
Watering every third day alternating nutes and no nutes

I think it was not heat related but the intense light because the lower plant looks fine and the flowers on lower stems are growing much better than the main flower which is not growing at all. Also....some stems appear to be purple? Thanks to everyone as always.

Looks like light burn, or sun bleaching.

Tokey21 said:

Looks like light burn, or sun bleaching.

Click to expand...

I think you are right. Once I moved the light away the leaves started to get green. They were totally yellow 2 weeks ago. They got a lot of green very quickly but it has slowed. Thanks for the input. I will keep an eye on it...the rest of the plant is looking very good but I am a novice.

Not a problem. With air cooled lights you are able to put the light a little too close sometimes.