How much total light is the best for proper coral growth?

[reefer420]

I was in RCA yesterday when i overheard a conversation about how much light do corals require for the best growth. I heard the young man say that 2 hrs actinic,1 in the morning & 1 before lights out. daylight should be 10 hrs, I am no expert marine biolagist,I'am a landscaper so i did not give any advice on the situation. I run my daylights for 8hrs and my actinics for 1hr "30/30" and my lunars overnight. Please tell me that I am doing this right.

[muddybluewater]

I run my actinic 12hrs, mh 9hrs, moon lights opposite of the actinic and my fuge runs for 16hrs, all night and part of the morning

[Derekreefer]

I run Actinics for 12 hours and daylight (10K) for 8 hours. I like to overlap the actinic and daylight as the daylight only does not look near as good as the two together. You want the blue spectrum to simulate conditions at lower ocean depths.

[Timfish]

This subject can really be a can of worms but I don't see anything wrong with an 8 hr schedule. Sprung and Delbeck in their first volume of "The Reef Aquarium" have some charts of sunlight on a reef and it shows how a lot of light is reflected off the water surface in the mornings and afternoons and I guess someone could use that to make an argument for just a 4 or 6 hour schedule for the all the lights being on. I like a 10 or 12 hour schedule myself with actinics only before and after. Have you asked your corals? Seriously!, take a picture of your tank when your animals are all expanded, change your timers by an hour or two, keep taking a picture each week for at least a month and see what changes you're getting, then change your timers again and repeat. If you don't see a real noticable difference there's an argument for going back to an 8 hour schedule to save heating issues (if any) and maintenance costs.

[+dapettit]

This is just my opinion. And remember what may work for me may not work for you. As Mcallhan would say "It depends on your tanks personality."

I beleive it depends on several factors. If you run you lights for any length of time water temp will rise. If there is a huge swing in temp you'll need to incorporate fans or a chiller.

I run my actinics for 10 hours, 1 hr before lights on, 1 hour after lights off. I run 2 MH 250 lights for 8 hours. One coming on 30 minutes before the second and the same light going off 30 minutes before the second light. My fuge runs from 9pm at night to 3 pm the next afternoon or 1 hour after lights out and 1 hour after lights on. My temp swings about 2 degrees. I have 2 - $9.99 fans in my canopy and 1 in the sump.

I tried running my lights for 12 hours by increasing the photo period by 30 minutes per week. The lower SPS loved it but the SPS at the top was getting burned tips. Also my acans became recessed. So I backed down to my current photo period. My corals are fat, dumb and happy.

Experimentation and good record keeping will help determine which lighting schedule will work best for your tank.