Photoperiod and Polyp Extension

[malx]

Hi, Everyone.

So to solve my Stony Coral growth issues once and for all I'm being as consistent as possible as well as looking under every rock that is unturned to see what the issue might be. Generally, I have decent growth and color, but I can't get it from decent to great. I have had the best results when my Phosphates were around 0.03, but since then they have elevated to about 0.1. My acros (aside from the ones that died) seem to not be bothered, and I do know some local reefers that have had high phosphates and no issues with their acros. They are growing, slowly, encrusting, and the tank is chewing up Alk. I am working to slowly get my PO4 down, however, there is one thing I am trying next, and that's lighting.

Forget about PAR, because I run a 6 Bulb ATI Sunpower with 3 Blues, 1 Actinic, 1 Aqua Blue Special and 1 Coral Plus. Local guys that see my tank agree that my lighting intensity is not an issue. Two Kessil A80s ramp up and down to 80% intensity and 40% white but that's mostly for shimmer as these lights won't penetrate too deep on a 20" tank (they are nano lights).

Before asking my question, please know that I do understand the following:

• Too intesne light is bad.
• Too harsh light from LED is bad.
• The blue spectrum is what grows coral, and there is plenty of that in the two white bulbs I have
• Too little light will turn corals dark
• Too long of a photo period will have diminishing returns. In more detail, after 4-5 hours of intense light, corals will stop photosynthesizing until the next photo period.

After reading about some people's lighting schedule, one person I respect very much in this hobby, G. Alexander from Germany (if you run ZEOvit or have had a KZ product in the past know this guy) only ran his lights 10 hours a day. So it got me thinking...

My question:
Could my lack of PE and overall struggle for success be because my lights are run too long? I only run 5 hours of full intensity per day, but but 6 hours before that and 6 hours after that I had my lights on ramping up from 0 to about 50% simply because I wake up early and go to bed late, and I like looking at my tank. Is it possible that even though my light is not intense enough to bleach corals, is the long light schedule not giving the corals enough time at night to recover from the day? Could they be not getting enough darkness to comfortable extend their polyps long enough, and eventually succumbing to STN?

What are your thoughts on my question?

Thanks!
Joey

 

[Uncle99]

I would agree with your thinking, maybe your robbing your corals photosynethic time with the highly extended Ramp on both ends. Your correct, rest is as important as growth, same with plants,stability to me is most important. I only ramp 1/2 hour on each end with 8 hours full intensity with 15 hours of rest. Of course, if you do make a change, very slowly.

Even at the equator, corals get only 12 hours full intensity.

 

[thegrun]

Your overall photoperiod is a little too long and also your peak intensity duration is too long. Shoot for a 3-4 hour peak along with a 4 hour ramp up and down, to more closely match the conditions found in nature.

 

[Tastee]

Interesting thread Mcgyver, thanks for starting it. I run my lights for a reasonably long period, and this has me wondering if it is too long. I have a 53g Red Sea Reefer 250 display, 21” deep, and Maxspect RAZR 240R lights (3 clusters). Not sure of PAR output sorry, don’t have a way to measure that ATM. The A channel is white, the B blue.

My cycle is:
1. 01:00 A 0%, B 0%
2. 09:00 A 0%, B 0%
3. 11:00 A 20%, B 30%
4. 12:00 A 50%, B 50%
5. 21:00 A 50%, B 50%
6. 22:00 A 0%, B 1%

I initially misunderstood how the RAZR cycle works and had a far more gradual ramp down, and moon light all night, and the corals got very little low light. When I changed it to the above cycle they became much happier. I only have a small amount of corals at the moment, a mix of leathers, mushrooms, Zooanthids, a softie and a brain.

Any suggestions of changing this would be gratefully taken on board.

 

[Uncle99]

Keep it simple. Your light does not have to mimick the earths photoperiod.
What is important is that each 24 cycle they should rest at least 12 hours and they dont care about the ramp. I have 1/2 hour blue, then full intensity for 8, 1/2 hour blue, been this way forever. All corals fully extend and retract at night each day.

 

[FullBoreReefer]

My schedule is...

2hr ramp up
5hrs “max” lighting
1.5hr ramp down