In 2 days time I'm due to put in the PK 13-14 and canna's Boost Accelerator, i've been offered the use of a 1000w HPS too do you think that would be a good time to put the light in?

My plants are getting really tall, they're getting a little bit of burn where the plants are condensating. I've put the light up but it wont go much further up the tent......