i would like to start off by saying DONT FUCKING USE SECOND HAND HPS GLOBES yes thats right i beleived the prick who sold me the complete second hand light units when he said "those globes have hardly been used man you should kick ass with those lights" yea right pal ! so any way ,it turns out that my globes bassicaly had no lumen output, or bugger all any way ! being my first grow i thought they started off doing fine but after a couple of weeks growth and a few questions to more experienced growers i soon discovered they should be twice as big as they are . and 150$ worth of new globes later, they are coming good tremendously fast,before i got new globes they only grew about 5cm in a week , now after only two days with newbys they are growing 2-3 cm per day and getting better! at this stage (34 days ) i was hoping to have switched them to 12/12 lighting but now ill have to wait at least 10-14 more days. so any one out there thats thinking of buying second hand lights make sure you put new globes in em !!!! unles maybe you know who youre buying them off and know how old the globes are. so until next post update bye all........