you could if you wanted to. it will perform under both lights MH or HPS.
HPS has more of the red spectrum to encourage it to stretch though.
check out CMH for spectrum and lower watts used.
Good Luck.
Definitely run both lights as they start to flower but keep them lowered down to 600 watts each. If you only have one ballast I would wait until you see button size buds before switching over to the hps