i am looking to upgrade a my grow a bit. i currently have a 30"x 18" grow space and i am looking to upgrade to 3'x3' tent. currently i use an old style mars hydro 300 and ebay cheap light of equal power draw. together they pull about 285 watts. i would like to add some more light in the tent. the research to more confused and indecisive i get. my cheapest route would be to add another mars hydro for $60 and add another 135 watts. after some reading many people claim that cob leds are the most efficient leds out for growing but they are quite expensive. i can make my own cob leds for about $170ish for 150 watts using the cree cxa3070. there exist another group of people aren't really all that great due to the fact they they don't have very much canopy penetration. i would really hate to spend $180 on lights that aren't that great. i could also scrap the leds all together and just get a 400 watt hps with an air cooled reflector for about $300 for the whole setup fan included. another opition would be to just upgrade to something like a ($350) mars ii 900 which pulls about 385 watts at the wall according to the website. my main goal is to get the best light per watt at a reasonable cost.