since you are using an open reflector I would drop the second 400W and just stick with 1. I would also drop the light about 8" or so. If it was a cooltube or such u might be able to do something a lil different but like it was already pointed out that 3 plants be fine under 1 light.
tinytoon Reviewed by tinytoon on . Wattage vs Heat in 4x4 grow tent I have a 4x4x7 grow tent and use a 400MH for Veg and 400HPS for flower; I am 4 weeks into flower and just put the 400MH back in with the 400HPS; 800w for the last 4-5weeks. Just 400HPS my temp is 81c(day) 69c(night) both 400HPS and 400MH my temp is 89c(day) 69c(night) Where do we draw the line with heat vs wattage. do i keep the extra 400W and take the increase to 89c?? Rating: 5