Is a consistent light cycle a must?

To a point, yes. The temperature ranges we are talking about are seriously a degree or three, but that's over the range of the year (summer/winter seasons). Where you run into trouble with temp. swings is when you are varying say, 5 degrees in a single day.

Consistency is a general rule of thumb, and a good one to follow. I would not start making drastic changes to your tank, but when or if you decide to make changes, do them slowly over time. You don't want to change too many variables at once.

 

This is an excellent topic!

Have you ever seen lights that run on rails and slowly move over the tank? They're amazing and geez, talk about sophisticated. I also talked to a guy several years ago who told me you can buy some type of programmable box that will make your lights replicate different types of natural light, ie: cloudy days, rainy ones, hot-bright days etc. I've also talked with several divers who say it's not always as sunny as people think although that might just be due to where they were diving.

Years ago I got into a discussion with several people regarding light and coral growth. One of my questions was, should they always grow at a fast pace? Are they supposed to? Is that natural? We all were just tossing ideas around.

My light system was a combination of t5s and halides. Most days I did the typical 2 hours of t5s, then added the halides and ran all of them for ~ 5 hours and then turned the halides off and did the final 3 hours with just t5s (I ran my lights about 10 hours). However, when it was cloudy or rainy where I live, I didn't turn them all on. To me it just seemed like the natural thing to do.

I cannot give you scientific answers because I'm not a scientist but it sure is a good question!

 

Sorry, one more thought regarding your original question: logically it would seem that the lights should go on at around the same time everyday and go off at the same time as well. However, let's say that in nature on one day a storm may be occurring in the morning thus it's dark outside yet the clouds lift later in the day and it gets sunny. So, on a day like that the intensity of the photo period wouldn't really start at the same time as, say, a typical sunny day. Or, the reverse could occur and after 3:00 pm it gets really dark and stormy out and there is very little light outside. Then the intensity of the photo period got shortened quite a bit, once again changing the "normal light schedule". Does this make sense? Or, I could just be bonkers and not thinking clearly at all! lol

 

Hi, Lady J. It is a great discussion, and it's nice to see others joining in.

With LEDs nowadays, having multiple colors and channels has allowed us to replicate the weather like you mention above. It seems almost standard with LEDs, for most fixtures to come controllable (by default) and/or at least with some degree of preset features for this purpose. Of course, the more you're willing to pay, the more sophisticated a fixture you're likely to get.

For example, while my BoostLED par30s are only on/off, the Ecotech Radion, Maxspect Mazarra, Aqua Illumination fixtures all come with storm/weather settings and can be controlled even more precisely with an aquarium controller and/or writing your own code. Some fixtures (depending on the manufacture) will let you share files and use other peoples' code on your light fixture.

3reef member, Biocube, built a DIY fixture from Rapid LED and then used coding software to input a storm mode to his Typhon LED controller to run cloud-cover/storms from his fixture over the tank.

As for leaving lights off for a day or two, while I do not do it myself and many may tell you otherwise, I agree this will not result in negative effects on your coral. People sometimes do several-day blackouts in order to resolve algae issue on their reef tanks, depending on the degree to which it becomes an issue. Of course, this does not always completely solve the problem and I would not do this all the time. Our corals are (or can be) hardier than most assume.

 

Excellent information, thank you! The technology of this stuff is quite amazing, it really is. I always wanted to switch to LEDs but darn, good ones are a wee bit expensive (and you can't put junk over a reef IMHO).

I had an algae issue once and did the 3 day blackout and it worked very well. I agree with you that corals are hardy and a day here or there without lights isn't going to kill them. I guess that if we look at Mother Nature, well, it's just not really "normal" for every single day to be bright and sunny (except perhaps in the desert somewhere). I stated in the post after the first one I gave that it also doesn't seem natural to have an identical photo period everyday either, but again, I'm not a scientist. It's my humble opinion that if we truly want to replicate nature, we should try to, well, replicate it and that may mean changing things up a bit. It would be awesome to hear from an expert in this area because quite truthfully, I have no idea! :

 

While "replicating Mother Nature" sounds intriguing, I have to wonder if there are any true benefits. For example, when I switch my daylights off in the middle of the 'normal' photo period to acclimate a new fish, my corals simply close, the same as when the lights go off at night. Doesn't really hurt them, but it also doesn't seem to have any positive effect, either. Personally, I consider it similar to a tree in a hurricane- it's just something they have to endure in the wild, but not anything they need for survival or good health in our tanks.

 

Yes, very excellent point. I think we should just ask the corals straight out what they want. ;D