The ceiling is I think 6'8", so there is about 4 to 4.5 feet from the top of the grow tub to the ceiling. I know how long to veg the plants, but what I am wondering is at what size or how many days will they have to be under the CFLs before we can throw on the HPS. I don't want to fry the seedlings but I'd like to get the better spectrum from the HPS asap.

Also, what do you think of my setup? Will it be enough fans to dissipate the heat? We were also going to put an oscelating fan in the middle of the room to blow back and forth across the table.