just one bulb i have 4 ati blue plus one white 2 fiji and one blue all 80 watt bulbs so very bright. ,,want a bulb that is like a minature version of a vho that will give me that same pop i get from my metal halide tank i run ushio bulbs with 2 vho acticnic type bulbs and the color is dead on ..my t5 look great just not enough pop or so it seems ..