how many hours a day for metal halides?

[banditpowdercoat]

12 hrs here, the 150W's are 12hrs, 10am-10pm, and the 250W is 7 hrs, 2-9pm

[BlueAbyss]

I've been running my 70W for 10 hours.

[Zoaelite]

During the summer time my 400W DE fixture runs 12-6 I extend it to 11-7 during winter months. Supplemental actinics have about a 2 hour buffer zone on both sides for a dusk/ dawn effect. My Tek 5 system is on the same schedule.
Levi