Are There New Ideas on the Subject ?

A couple of yeas ago, when I started my SW tank, the rule was 8 hrs. of light per day. My corals are not doing very well. The parameters are good & the light is new. It is on 8 hours/day.

Should I be running it longer ? How much longer ?


Thanks.

 

I run my actinics for 13 hours a day and my daylight bulbs for about 12 hours a day.
In the equatorial regions where a lot of the coral we keep is native to - the photoperiod is nearly an unwaveringly perfect 12 hours/day.

 

What type of lights? how deep a tank? What kind of corals. The justification for short photo-periods is that corals photo-saturate, and there is little if any useful benefit to extended photo periods once photo-saturation occurs. Possibly even added stress. If your corals are not photo saturating, there is probably a benefit to a longer photo-period.

Personally, I think that there are other factors at work. Light sets an organisms circadian clock, which is responsible for many metabolic functions. Most in the hobby don't consider this, but personally, I suspect a natural light cycle is important for growth and long-term health. I think full output is only needed for a short time, though, as this corresponds to the brightest parts of the day. probably could even just be around 4-6 hours, but IMO, there should be some light for 10-14 hrs per day, even if just actinic. Certainly others will disagree though.

 

+1 to M-Oceanman. I believe they do need at least twelve hours daily. personally my lighting period goes as follows. Actinics 10am to 10pm, Daylights 12 noon to 8pm and moonlights from 10pm to 10am. I also believe to help with ph balance at night and to give macro a proper photo period in the fuge my light runs opposite the actinic cycle of my DT. I wish I could afford the best lighting outthere so I could have a nice dimming set-up to really emulate the truest lighting for my animals. I am still new but have not lost anything in 6mos and everything is thriving and growing well.

 

I must admit that I am guilty of not having a regular light cycle. I have them on for 8 hours, but I do not usually turn the light on & off each day @ the same times. I'll have to invest in a light timer. I have a zoad that is doing well as is my mushroom. The ricordea is beautiful, but not growing @ all. My button coral died. I have a sea anenome that is huge & I have only a 10 gallon nano. My clown fish really enjoys him.I do notice that some corals shrink after a certain period of light. Perhaps they trying to tell me that they have had enough light.

 

My LFS told me that, if my reef tank was near a window, antics were unnecessary. He said they are more for aesthetics than anything else. Google bears him out.

My bright light is a coralite 29/60. My tank is an 8 gallon nano, 16" deep.

After 8 hours, some corals fold up & look like they have had enough. Others are still doing fine.

Would it hurt the corals who looked like they have had enough, to run the light for a few more hours ?

 

And this would be exactly why a lot of LFS are not to be trusted, or at least their advice taken with a grain of salt.

Actinics are more aesthetics than anything - however - sunlight filtered through at least three panes of glass (two if you windows are insulated plus the tank itself) the spectrum has shifted far from the natural spectrum/intensity/PAR of the sunlight. This is why if you do put a tank near a window, the wall of the tank furthest from the direct line of sunlight tends to get much more algae than the other panes of your aquarium. If you need to grow algae - then sunlight through a window is ideal.
But then again most of us do not want to add a "natural" and "unpredictable" element to our systems because the aches and pains we go through are such that we CAN control everything (i.e. temperature, salinity, O2 exchange, lighting, etc). Point being even if you do get "ideal" and relatively "constant" sunlight - it's generally the wrong spectrum for a reef tank anyway.

Going to HD or Lowes and splurging on a $15 timer for your aquarium (perhaps 2 if you have actinics and daylight lamps on your fixture now with two different power supplies) will be the best money you have spent to date on your setup.

Not only will you be happier to not have to remember it - but your corals will largely benefit from a regular rhythm of light/dark.

 

There is quite a bit of debate over whether actinic lighting is just for aesthetics or if it necessary for coral photosynthesis to occur. I'm of the opinion that it's not just for aesthetics.

 

Actinics do help certain coral in growth and almost all benefit from color enhancement. I would suggest actinics for 10 hours and daylights for 8.

When is the last time you changed bulbs and what are the bulbs you are using. looking for manufacturer and spectrum type including Kelvin rating.

 

I have to agree - and this is why (just observation)

My favia and brain do not open up fully with actinic light on. Also my torch coral stays out during actinic lighting cycle.

Seems to have an effect - my xania start to close up (then open when lights are off after an hour or two)