very light colored growth

my friend has some nirvana superskunk plants three feet under one 1000 watt hortilux hps .
the plants are bleaching like crazy and a lot the very top leaves look very light and so do some upper internodes . they are currently in flower for about two weeks now .

pH = 5.8
ppm = 860
temp = 73

using gh flora three part = (g-m-b) 1-2-3


the light is three feet from the tops. but the bulb was switched back to 400 yesterday and they seem to be "greening up" . so how can i run the 1000 ? do i raise the ppm of the nutrient solution ? what do i do ? im going to get some skimpy buds if i cant run that 1000 watt bulb at least ... i'd like to run all 1800 watts of light that i have to get the most and highest quality buds ! thanks for the replies so far ! -peace-

strain = nirvana superskunk vegged for 5 weeks from seed under a small hydrofarm 400 watt metal halide
i had laying around

setup =
2 x radiant 8'' air cooled hoods
3 x hydrofarm ballasts (430 and 1000 plus a self contained 400 watt MH hydrofarm fixture)
1 x hydrofarm megagarden
1 x 800cfm inline fan
lots of gh nutrients

The largest light I use is a 600w HPS but from what I know, 2-3 feet above the canopy should be an adequate distance for a 1000w (and depending on air cooling/glass)... When you said they were switched back to a 400w, I assume that 400w is what they were vegged under before the 1000w was added (enjoy that run-on sentence)? Curious if you took any steps to let the plant adjust to the switch to the 1000w?

yeah i changed it back to the 430 hortilux hps . right now the room is 73f , humidity is 45% and the res temp is around 72 . the 430 is in the air cooled hood 3 feet above the plants . i just reach in the hood and switch the bulb out and then switch to a different ballast . thanks for replying

oh yeah i did let them adjust for a week by running both 430 and 1000 (but not directly hitting the plants) for a week when i was running the 2-2-2 transition phase nutes .