Odd color issue

Hi All,

One of my plants is exhibiting an odd, neon green discoloration that is quite prevalent around the mid-vein's on my leaves. It's basically a bright green area eminating about 2-3mm outwards from the midvein. Then it stops and there is a stark difference between the rest of the leaf (a nice green healthy color). I have looked through several guides and have a few ideas but not exactly sure. It is mostly on the newer growth, but goes away a bit as the leave get older. Aside from that, the plant looks great.

A few specs:

400W HPS
Soil, 2 gallon pots, using techniflora's recipe for success.
Vegged for 8 weeks from seed using 4 different strains.

Temps:
It does get a bit hot, around 83F ON .
Humidity: 50%

Possible causes:
maybe temp?
I did check the water that came out the bottom after I watered and it's PH was around 6.2-6.3 although I make my water and nute solutions around 6.6-8.

Any ideas are much appreciated.

ride it out see what it does

Find the thread on PH balance on here and you will find your answer. In my case I had all of my plants doing this, after watering them with tap water that was WAY TOO HIGH in chlorine and other elements that change PH and lock nutrients out.(I let them sit open for 5 days and still issues). Use distilled water for a while and skip the tap. You will see the older leaves will never fully recover but the newer ones will be lush and green again. I would also suggest a PH test kit for future use. If you do not take action the nutrient deficiencies will eventually claim your plant. I sacrificed a NYCSD clone for this experiment as I am from NY and am in WA state. The difference in water quality is astounding, as NY has the best water in the country. Over here it's bottled or nothing, hell I can't even get a good pizza due to this shit, I have to make my own from bottled water.....monotonous.