If it is what I think it is, you won't believe me...

There was this system that ran 4 600 watt bulbs over a 4 foot x 4 foot area. Andthe lights were kept at about 4 - 8 inches from the tops of the plants.

Well the tops of the plants lost all their pigment..

IT WAS TO MUCH LIGHT!! This happens to plants at HIGH elevations that are closer to the sun.... It supposedly is just to many damn lumens and the tops of the plants turn yellow/white. They don't die or suffer any necrosis. If you pull the light away even an inch, the plants get their color back.. see how the plant in the middle that is closest to the light is the lightest... that's what clued me in...

Now the problem with this theory is that you are only using a 150 watt bulb...
go figure.. just my 2 cents...


I took a close look at the pics...do I see red stems? You can take some of your soil and stir in water .. let it soak for a couple hours and use a PPM meter on the water...
I think this works... and you can find out your soils ph too...