My garden is 3'x4' it is lit by a 400w HPS. Im happy with how my plants grow, sort off. Last week I smoked some med from a despensery, stuff grown under a 1000w, I can deffently tell the difference in bud density. My buds are nice and my med is strong, but more watts works better. Now my question would I be better off adding another 400 or just use one 600? I dont want to go TO big, cause more watts means more heat and than i got to buy a bigger fan. You input would be helpful.