1st Grow. Northern Lights

I'm about 3 days into my first grow and heres what I have done so far. For the box got a 27l'' X 15w'' X 32''h shed like thing made my Black and Decker. I first started out by lining the inside of the box with Mylar reflective material and cutting a hole in the top for my 150W HPS light. I then mounted two fluorescent bulbs one 27W and the other 30W. I also put in a and a 75W florescent tube. For cooling and circulation I only have one 4'' duct booster, but I am planning getting another 4'' and 8'' duct boosters. I'm going to use the two 4'' boosters for intake and put the 8'' at the top for exhaust. As the plants grow I am going to move the shelf down. After germination I placed the 4 seedlings into soil plugs and put the plugs into meri-grow organic soil. I am using flora nova grow for nutrients and I am currently watering the plants at 310ppm. Temp. is at 80*f and Humid. about 43%. The Seedlings have been under only the florescent lights and I was wondering how long I should wait before I turn on the high pressure sodium light. How does everything look? Suggestions?

Sorry about the pics being so big. Also, should I put each of the plants into individual pots? Or is it ok for them to be together in the large pot?

Individual pots. If you put them together they will compete for root space, and you'll have to chop up some roots when you transplant.. thus stressing the plant.