OF COURSE!!!
Dude, the more light, the merrier.

If you're flowering with one 1,000W HPS, and you add a second 1,000HPS, buds will be bigger.

If you have a 1,000W HPS for flowering, and you add a second 1,000W MH, buds will also be bigger.

The question is, which option would be better?
HPS + HPS
or
HPS + MH
?????

But dude, if you've got the bulbs, plug them IN!!!!
turtle420 Reviewed by turtle420 on . MH AND HPS during flowering??? I have a 1000watt MH system with a conversion bulb in currently for flowering. I heard a nasty little rumor that if you run BOTH MH and HPS to run BOTH spectrums of light during flowering that your buds will be more potent... Is this fact or fiction. If fiction, what CAN you do to ensure maximum potency? If fact, I have a 400 watt HPS with conversion so I can run 1000Watts of yellowish orange light and 400 watts of blue. Rating: 5