how long do i leave my lights on for?

[reefer123]

i have a 65g reef and i just got 2x250watt 15k metal halides, with no other lights.

what would be a good time to come on and turn off? :notsure:

 

[celacanthr]

You will need em to stay on 12 hours so you can have em turn on at 9-9 or 11-11 or 2-2 ... whatever fits your schedule.

 

[ezee]

Celacanth,
I have heard that running your lights for too long can lead to problems. It seems like he has a ton of light in there. Why so long?
Thanks!
E

 

[celacanthr]

depending on who you ask 10-12 hours but i lean on the longer time but 10 is supposed to be just as good.

 

[reefnut]

I'm just the opposite and lean toward the lesser side with MHs... I would leave them on 9-10 hours with no actinic's... with actinic's I run my MHs 8 hours with the actinic's running an additional 2 hours for a total of 10 hours.
Really it's what works best for your system. If the tank was up and running before you got the MHs you will need to acclimate them to the tank. Start at around 4 hours or so and slowly increase them over the next several weeks.