Longer photoperiod VS. PAR increase for coloration

[SamMule]

Will increasing photoperiod have the same effect on coral coloration as increasing PAR? Trying to pull a little more color out of some of my higher light acros, and considering running the T5's for an extra hour in lieu of adding another bulb.
Thoughts?

 

[Breadman03]

I don't know the answer, but spend some time looking for info on "DLI." Some of the threads on the Neptune PMK might also have the info you're looking for.

 

[blasterman]

The accepted concensus for now seems to be photo period and light intensity are pretty linear in relation to each other. Even when you follow these trendy new light schedules on LED fixtures where light is ramped down for short periods all it does it just extend the total light period by the same amount of time.

Maybe Dana has seem some differing data,

 

[Spare time]

Im interested in this thread. From my understanding, it is intensity, not duration that causes the increased coloration.

 

[Spare time]

You might enjoy this video

 

[Rubberfrog]

You might enjoy this video

This is fascinating. It's all way above my paygrade.

 

[A. grandis]

Will increasing photoperiod have the same effect on coral coloration as increasing PAR? Trying to pull a little more color out of some of my higher light acros, and considering running the T5's for an extra hour in lieu of adding another bulb.
Thoughts?

There is a balance for color that will embrace everything in the system between water quality and light. Each species of coral will respond differently to that balance as well. Some times to the individual level!! Position of the corals, depending on water movement and alkalinity will also play big time with colors and growth!!! Nutrient import/export will have a place in the equation as well!!
Changing PAR alone isn't directly related to changing colors necessarily either! Most of the time to be able to change PAR you need to change spectrum in the first place, which will again have deep influence in colors too!
So this thing that people try to summarize about PAR alone has to be seriously reconsidered! Not to mention the differences those measurements could have between sensors and PAR meters, distances, etc...

Trying to help you in a practical way... changing your bulbs could change PAR, but spectrum as well... that could change the colors of your corals after a certain period of time... that will depend also on your water quality/stability of the system... which can change any time if you do not control that stability closely.
Low PAR bulbs, like ATI True Actinic, can change colors!!!!
Photoperiod is a very touchy subject. Be careful changing that and PAR (DLI) at the same time!!!!
You will need to allow some time to be able to see any changes. Some times close to a year for certain species. That will depend on the stability of your system as well..
Make sure your water parameters are great and stable and keep it stable for months before you change any bulbs. You might get THAT color you are looking for just by adjusting parameters and by keeping the water stable enough.
Good luck!

 

[SamMule]

There is a balance for color that will embrace everything in the system between water quality and light. Each species of coral will respond differently to that balance as well. Some times to the individual level!! Position of the corals, depending on water movement and alkalinity will also play big time with colors and growth!!! Nutrient import/export will have a place in the equation as well!!
Changing PAR alone isn't directly related to changing colors necessarily either! Most of the time to be able to change PAR you need to change spectrum in the first place, which will again have deep influence in colors too!
So this thing that people try to summarize about PAR alone has to be seriously reconsidered! Not to mention the differences those measurements could have between sensors and PAR meters, distances, etc...

Trying to help you in a practical way... changing your bulbs could change PAR, but spectrum as well... that could change the colors of your corals after a certain period of time... that will depend also on your water quality/stability of the system... which can change any time if you do not control that stability closely.
Low PAR bulbs, like ATI True Actinic, can change colors!!!!
Photoperiod is a very touchy subject. Be careful changing that and PAR (DLI) at the same time!!!!
You will need to allow some time to be able to see any changes. Some times close to a year for certain species. That will depend on the stability of your system as well..
Make sure your water parameters are great and stable and keep it stable for months before you change any bulbs. You might get THAT color you are looking for just by adjusting parameters and by keeping the water stable enough.
Good luck!

Thank you! What you said here pretty much reinforces what I've been seeing with my tank.
I would like to run 4 bulbs in my fixture. For two reasons. One; I like the whiter spectrum during the day.
Two: I would like to get a little more light to some of my acros. The highest ones are at 300-320 PAR. Most are 220-260.
Parameters have been very stable for maybe 5-6months. (Would have to look back and see when I dropped my alk down)
However, each time (twice) I add a 4th bulb to my fixture and dial down my LED strip to 75%, I start to see many corals respond negatively. Decreased PE on my euphyllia and some bleaching in my montiporas. The total PAR increase is only ~10%, but the spectrum is obviously different.
So... My thought was to leave the T5's on longer (same spectrum) and hope that the extra time under daytime lighting would have the same effect as an increase in PAR without the negative effects of a change in spectrum.

 

[A. grandis]

Thank you! What you said here pretty much reinforces what I've been seeing with my tank.
I would like to run 4 bulbs in my fixture. For two reasons. One; I like the whiter spectrum during the day.
Two: I would like to get a little more light to some of my acros. The highest ones are at 300-320 PAR. Most are 220-260.
Parameters have been very stable for maybe 5-6months. (Would have to look back and see when I dropped my alk down)
However, each time (twice) I add a 4th bulb to my fixture and dial down my LED strip to 75%, I start to see many corals respond negatively. Decreased PE on my euphyllia and some bleaching in my montiporas. The total PAR increase is only ~10%, but the spectrum is obviously different.
So... My thought was to leave the T5's on longer (same spectrum) and hope that the extra time under daytime lighting would have the same effect as an increase in PAR without the negative effects of a change in spectrum.

To increase the T5's time, having them covering the entire surface area of the tank, is the way to go, if the corals need more light. It's all about balance and adaptation.
Photoperiod can go from 9 up to 12 hours using T5s only.
Use your LEDs only for that visual effect you like with the lowest percentage you can live with. The LEDs are unnecessary and will do damage before give you any benefit if the light is already enough using T5s. There is no way T5s will bleach your corals unless you don't respect adaptation to new bulbs or to a longer photoperiod, of course. LEDs in another hand can cause bleaching even after a while, with a bit more of what the system can handle those LEDs in that particular time frame.
Use your T5s only for a week or 2, then add those LEDs at 10% for a small period of time a day and increase through weeks watching your corals. Remember: results will take a while to show anyways. Your corals are living organisms. The less you use your LEDs the safer/easier.