How may hours of light do I really need?

[trigger0214]

Hi all,

I've recently moved my tank into the kitchen to do some work on my dining and living room floors. Being too lazy to hook back up the timer, I've been running the lighs manually. Say, between 4-8 hours a day. The tank does get some natural sun light through the window later in the day (on the west side of house, back of tank is painted black).

I have noticed that there is much more coraline alage growing (maybe in part to the carpet anenome eating the urchin) and less nuisance alage.

So, my question is how long does a 250 wattt 15K MH need to be one a 46 gallon tank....I have crecea clams, xenia, etc, all doing fine.....

 

[Unarce]

I've dropped mine down from9 to 5 hours a day now. If I had actinics, I'd probably run my MH at 2-3 hrs, and the actinics for about 5-7 hrs. 5 hours of MH seems to be plenty.

 

[Anonymous]

I was running my MH for 6 and my actinic for 10 on my last tank and that seamed to be fine.

 

[Anonymous]

I run my halides for 8 hours and the actinics for 9.5 hours.

 

[Meloco14]

I recently read somewhere that there is a theory that corals only absorb a significant amount of light energy for a couple hours when the sun is at its peak. For this reason a lot of SPS guys have started cutting back their photoperiods to 4-5 hours without any noticeable loss of growth or coloration. I don't know if this is scientifically true or not, but I think you will be fine with 4-5 hours a day. Worst case is your corals will start browning up, and you can increase the photoperiod to get them back to normal coloration. JMO

 

[Unarce]

Funny thing is, my purple monster never looked better after I cut back the photoperiod

 

[Meloco14]

Well, you know it does make sense in a way. I mean I would think the symbiotic algae living in the coral only has so much capacity for energy absorption. After taking in their fill of light energy all that excess radiation beaming down on them might actually do some harm. But, what do I know. I didn't pay attention in my marine bio classes. I'm lucky I graduated on time :lol: . We need someone like Sanjay to do a study on the most efficient photoperiod for sps corals in home aquariums.

 

[Unarce]

I used to use this study a lot during discusstions on lighting:

http://www.science.uts.edu.au/des/Staff ... hesis.html

Makes even more sense to me, now :wink: