i looked at the bulb and it says 400w on it. and the stickers on the ballast says "selectable voltage" and 60 Hz, 120V, 3.80A not sure what those mean but thats all thats on there.. but if its a 400w mh,, how many sq. ft will this properly light? and when i start to flower, can i pull out the bulb and switch out to a 400w hps light?