Photoperiod intensity vs duration

NastyZ

Member
So iv been wondering if a high intensity photoperiod that runs for shorter time is the same as lower intensity photoperiod that runs longer I know coral can only consume so much light then it starts to get damaged so which is better or are they the same for color and growth
 
I have taken the approach of having a long photo period with a short duration of high intensity. With an LED fixture it is easy to set up. I run 14 hours from when things start to ramp up to when the end the ramp down. Only 4 hours are at full power.

My basis for that decision was the sun intensity varies parabolicaly during the day, in the tropics sun up to sundown is 12 hours all the time and there is some pre dawn and after sunset light.

If that best for a home aquarium? Not sure.
 
Some of the best looking tanks are still old school - timer turns on MH which fully warm up in 2-3 minutes, run for 8-10 hours and then are off. Mine are like this - 500-600 par within 2-3 minutes and then off suddenly after 9 hours - I am not a dusk-dawn guy. I don't think that the color can get much better.

Quality will matter more than intensity or duration, IMO.

I don't think that there is a way to mess this up if the light is high quality.
 
Well for me I have an ati 8x54 powermodule and I'm getting between 400-600 to all my sps I run all 8bulbs for 8hrs and 2 actinics for 13hrs I'm wondering of in giving my corals too much light if I was I'm think I can shorten the time or raise the light
 
8 bulbs over a 90g is a bit excessive, but if you're corals are growing good with good color and not pale I wouldn't change anything.

I run my 4 bulb DIY T5s for 8 hours.......full on/full off and have good color and growth. My par levels are 200-450.

If you're having problems I'd raise the light a few inches and knock the actinics down to 10 hours.
 
I've tried everything from all lights on for 8-10 to slow ramp up and down. playing with a lot of arrangements over the years I've had my best results with color and growth with a 12 hr cycle with all lights on for 7-8 in the middle and blues on for 2hrs before and after(I run a lot of blue light).
 
I wonder myself if the whole ramp up/down led craze is partly to blame in them not performing even better.

Perhaps the simple "old school" mh style full on/off style is what us led guys should be running...?
 
I'm not talking about ramping I'm talking about short high intensity 5-8 hrs of high par (400/500+) with some actinic after vs 12hrs of lower par (200-300)

I also wonder why ati went with 2bulbs on one cord then the rest on another and didn't spread of the bulb controllability I think they were trying to go with the Mh concept
 
I wonder myself if the whole ramp up/down led craze is partly to blame in them not performing even better.

Perhaps the simple "old school" mh style full on/off style is what us led guys should be running...?

I do not think it is the idea of ramping up and down, but our understanding of how it should be done.

Mh style would seem a reason able approach with some history of success. I still like the ideal of a parabolic (or kind of) intensity change through the day. My tank is having positive results so far. Seeing that my tank started under LED with frags I think it will be interesting to observe the progression.
 
Here's what I have picked up from various Advanced Aquarist articles. If we want to emulate light falling on a typical coral reef in the tropics:

On a typical sunny day, the light period is ~12 hours, however, light doesn't penetrate until the sun is about 15 degrees up from the horizon and light stops penetrating when the sun is ~15 degrees from setting, so ~10 hours of actual light penetrating the water. After light begins to penetrate the 'ramp up' towards higher intensity is a fairly short 1-2 hours, ditto for the 'ramp down'. High intensity of 5-6 hours is typical, with temporary reductions caused by the occasional cloud passage.

I've had very good results following a '10 hr total/6 hr high intensity' schedule in my small mixed coral reef tank. However, corals are adpatable so following nature exactly is not a requirement for success.
 
Mammothreefer had a TOTM a while back where he was running 2 250w Radiums in lumenarc minis over a 65 for 6hrs a day. That was all, and that is an intense amount of light for that size. I remember reading an article by Sanjay (maybe even Riddle) that said PPFD is like rainfall. Short and intense, or long and moderate, as long as your corals are used to it, it is fine. I'm running DIY LEDs at a low amperage for 12hrs a day and a radium in a spider reflector for 4hrs a day, and my corals are doing really well.
 
Generalities:

High intensity for a relatively short time is required for some pigments to develop.

Longer duration (up to a point) can be used to make up for less intense lighting. Helps with growth and some coloration, but will not develop some pigments to their full potential and some possibly not at all.
 
IMHO 2 are the main factors involved with intense light:
1) effect on nutrient
2) pigments development (coloration)

the longer is the duration and the intensity the greater is the oxidation and therefore the decrease of the available nutrients.
this explains why with strong lighting for long photoperiods corals became pale and then starve.
With strong and long illumination you need to feed more because nutrients will be not more available.
If you feed more you will have SPS with good colorations.
The longer is the photoperiod the greater is the pigment development.
You need to find the right balance between light and nutrients.
 
All of these observations and pseudo-science are fine in isolation or academia, but unless somebody can quantify long, duration, intensity or what is enough or more nutrients, then most of this is worthless in practice. You are better off just making measured changes (small, incremental with weeks in between for observation) in your tank and using your own eyes.

I can tell you that from my tanks, I don't make any effort to go ULNS, but I do have clear results in both N and P test kits on Salifert and 8 hours a day of HQI produces wonderful colors and growth.

I really don't think that you can mess this up as long as the spectrum is good.
 

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