Do Not use a metal Halide bulb in a HPS socket that is meant for an hps bulb.They are 2 different ballast. I have used the hps for veg and flowering,and metal halide for veg and flowering. I'd get the HPS.You can use it all the way through the grow. You could get a swichable ballast and have 1 ballast and be able to use the 2 type bulbs.ONLY IF IT IS A SWICHABLE.

GA GROWN!