Photoperiod

[ALRHA]

I may end up getting 2x48" Spacelights, each containing 2x250W 10k and 1x150W 20k. I would set up my photoperiod as such to have a nice dawn/dusk effect and a full day of viewability (if thats a word). Let me know what your thoughts are.

08:00am: 1x150W 20k / ON
09:00am: 1x150W 20k / ON
10:00am: 2x250W 10k / ON
11:00am: 2x250W 10k / ON

09:00pm 2x250W 10k / OFF
10:00pm 2x250W 10k / OFF
11:00pm 1x150W 20k / OFF
12:00pm 1x150W 20k / OFF

12:00-8:00 - Moonlights.

[Flame*Angel]

That would be a nice lighting setup for your tank, especially considering the low canopy.

Your time schedule is nice and staggered. Overall the photoperiod is quite long though. In the ocean reefs the light is basically on for 12 hours and off for 12 hours - almost all tropical reefs are near the equator so this doesn't change much.

You might want to go a bit easy on the light at startup too. Too much light in the beginning can make the usual new tank algae cycles much worse.

[ALRHA]

well the two fixtures also make it easier to raise the light gradually. i can start with only one fixture on for a short while till i build it up to both on for the full time.
While the time may be longer than normal, 4 hours are the actinics which are more for our viewing pleasure than for the tank inhabitants. so it is 11 hours of full lights.
it may be longer than it naturally is, but would this necesarily have a negative effect? there are still 8hrs of total darkness (only moon light). wouldnt that be enough time for everyone to rest. maybe the corals may even appreciate the extra time of light.

[ALRHA]

oh, and the greatest reef on our planet, is the great barrier reef. it is not on the equator and likely gets more than 12 hours during its summer.

do people shut their light every now and then to simulate clouds?

does anyone have their lights on at different times on the weekends than during the week?

[Flame*Angel]

Check this article:
http://www.breeders-registry.gen.ca.us/Articles/v1_n3_tyree/tyree.htm

Scroll down to the heading "Sunlight Dial Time or Photoperiod". It's mostly technical stuff about coral spawning but it gives some information on what a normal photoperiod is. The maximum is from Cangaluyan Island, Pangasinian, Philippines at 12.97 hours. Great Barrier Reef is 11.2 to 11.4.

Anyway, the article is by Steve Tyree, a very respected guy in this hobby. His recommendation "The suggested captive system photoperiod range is 10 hours simulated day length during winter and up to 13 hours during summer." This is for the benefit of corals.

I suspect that the main problem with a much longer photoperiod would be excessive algae growth.

[ALRHA]

i will look at that link.
in any case i will be building up to that period. i guess if i notice algae growth, i can just stop extending.