just switched from HPS to ceramic lighting,, 3 315 watt cdl lamps produce more gram per watt than both a 1k HPS and 2 600 watt HPS .. i think after 20 years of growing hps has finally met its match.. the ceramic agro 3100k bulb lasts 20,000 hours, no bulb changes, produces tighter nodes in both veg and flower and is 35%more efficient than hps lighting... time to get away from hps, save money on electric bills, and produce better,bigger buds than ever..even beginners can easily get 1 gram per watt with ceramics and for those of you more experienced growers 1.5- 1.75 gpw is more realistic within one or 2 runs after learning how your plants respond to the new spectrum..PLEASE DONT GET ME WRONG,, I LOVE MY HPS LAMPS,, they served me well for many many years,,they produce great,stem bending indoor buds.. However the new ceramic lights, i was scepticle,,i thought it would be another waste of money like the money i wasted on led lamps years ago...but to my surprise they work,,,and better than i could have even hoped!!! many big grow ops are now going with ceramics,,simply more efficient and they work...