How long to run MH lights?

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bromion

Aquarium Advice Activist
Joined
Oct 17, 2005
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Los Angeles, CA
Hi all,

I was wondering how many hours per day folks recommend running MH lights. I have a 58 gal tank with depth ~2.5ft and one 400W 20k MH bulb. Currently the tank has only LR with some small corals, but I plan to get more more; eventually a clam would be nice.

I have read that it's unnecessary to run the MH lamps more than about 4hr per day. What do you think? Should I supplement this with PC or VHO lamps while the MH is off, or will NO suffice?

Thanks for any advice.

Jason
 
I don't think I've ever heard of only need 4 hours a day of your daylight lighting... most reccomend a 10-12 hour light cycle on an established tank.

If you're still going through your initial nitrogen cycle on a new tank, I could understand the reduced light schedule to try and cut down on the amount of algae you could get at that stage, but normally a 10-12 hour cycle is typical.

Myself, I have my Actinics on for an hour by themselves, then my 10k lights come on with the actinics for 10 hours, then just the actinics by themselves again for an hour.

HTH
 
If you think about it, the sunlight over the tropics is usually about 8 to 10 hours a day. In trying to re-create this in our tanks, the white light part of the system should be at least that. This allows your light loving corals to soak up the energy for the Zooxanthellae to thrive and feed the corals. Keep in mind that the darkness stage is just as important..Most of the reasons for having the blues come on an hour before and stay on an hour after is to create somewhat of a sun up, sun down effect.
 
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