too bright??

i have 2 600w hps in a dual cool tube. I basically let my girl get to big and now she is about 18 inches from the light. I have a thermometer at the highest point of the plant and temp never gets over 28.5 deg C. top of the flowers are looking bleached, white almost, with no burning evident. looks like there is no chlorophyl at the tips. could it be too bright up there?
lower flowers look fine hence my suspicion. thoughts?

if u only have one plant then yes that is too bright no need for a 1000 watts for one plant