Should light spectrum change throughout the day?

[AstroCoral]

I was under the impression that spectral changes occur in the oceans’ reefs as the sun rises, peaks, and sets. I mainly thought this was the case due to the atmospheric shift in color during sunrise and set. After watching a few in-depth BRS videos and reading some older articles from Orphek, I’m not so sure I understood this topic entirely anymore - does the water absorb most light leaving a constant spectrum for the reefs inhabitants regardless of spectral shifts above the air-water interface?

I currently run my AI prime light on a modified Saxby setting (lower cool white lighting due to my small tank size). BRS and Orphek have both stated that the spectrum should stay the same throughout the day and Orphek goes on to state that lighting spectrum does not change in natural reefs, just intensity. I’ve gone down a rabbit hole and have become more confused. Here is my lighting schedule for reference (corals started to bleach on me about a month ago, I lowered my intensity and adjusted the spectrum slightly which has led to some stabilizations in coral health - some tissue recovery but no significant growth)

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[W0terMoist]

When it is noon for Wherever you are, the sun is at its highest strength. It has less atmosphere to get through and you can feel it's intensity when you are standing in the sunlight.

When it is early morning, the sun is close to the horizon. Due to the angle, the sunlight has to pass through more atmosphere to reach you, which decreases it's intensity and changes the wavelength of the light causing the change in color. Also, due to the sun being lower in the sky, a lower percentage of the sunlight reaches the ground and the corals in the ocean.

So I roughly mimick this with my light spectrum on my tank. I have it take 3.5 hours for the light to reach max intensity, keep it at max for 5 hours, and then ramp down until zero for 3.5 hours. I don't have a smooth curve for the light intensity, but my corals do fine. The change in the color of the light due to the atmosphere isn't really the cause of the difference in intensity, it is more of a byproduct of the sun being lower or higher in the sky. It's position in the sky determines its intensity

When you think of it, when it is morning and the sun is peaking over the horizon, it is in fact day time, but the sunlight hitting the earth where you are currently at is pretty minimal compared to when the sun is above you.

When light enters the ocean, it changes its color spectrum just like how the atmosphere does. But since water is a different medium, it changes the light differently than the atmosphere.

I say, just don't over think it. Do some research on what lights you have and what other people with the same lights have as their schedule and intensity that works for them. That should give you a range for what you can do to your lights and probably get a similar result as others.

I am not an expert when it comes to lights and how the sun interacts with the atmosphere and ocean. So take what I said with a grain of salt.

 

[Cichlid Dad]

Also in no way an expert, here is what I do. I run t5 6 bulb. Bulbs are as follows. ATI b+b+true actintic aquablue special b+ b+. I run the first channel, the two outer bulbs b+b+ 7am tell noon, turn on all 6 noon tell 6 then back to b+ b+ 6pm tell 7 pm. This based on my work schedule no other reason. I get 260 par at the top of the rocks. It works for me

 

[90's reefer]

I was under the impression that spectral changes occur in the oceans’ reefs as the sun rises, peaks, and sets. I mainly thought this was the case due to the atmospheric shift in color during sunrise and set. After watching a few in-depth BRS videos and reading some older articles from Orphek, I’m not so sure I understood this topic entirely anymore - does the water absorb most light leaving a constant spectrum for the reefs inhabitants regardless of spectral shifts above the air-water interface?

I currently run my AI prime light on a modified Saxby setting (lower cool white lighting due to my small tank size). BRS and Orphek have both stated that the spectrum should stay the same throughout the day and Orphek goes on to state that lighting spectrum does not change in natural reefs, just intensity. I’ve gone down a rabbit hole and have become more confused. Here is my lighting schedule for reference (corals started to bleach on me about a month ago, I lowered my intensity and adjusted the spectrum slightly which has led to some stabilizations in coral health - some tissue recovery but no significant growth)View attachment 3162446:

That has to be the weakest setting for an ai prime that I have ever seen. It would explain very little growth.
How big is your system?
What corals do you have?
A pic would help.
I run all primes at first 4 100% the rest at 50%.
Great color and growth.

 

[Propane]

It does look to be well under half the original settings. When I backed my Saxby settings down about 10 to 15 percent it significantly lowered the PAR in my tank. From around 250 to 195. Pretty drastic for such a small change. Renting a PAR meter was one of the best things I’ve done when I set up my tank. It would be different in your tank of course but something to look at.

 

[AstroCoral]

That has to be the weakest setting for an ai prime that I have ever seen. It would explain very little growth.
How big is your system?
What corals do you have?
A pic would help.
I run all primes at first 4 100% the rest at 50%.
Great color and growth.

It does look to be well under half the original settings. When I backed my Saxby settings down about 10 to 15 percent it significantly lowered the PAR in my tank. From around 250 to 195. Pretty drastic for such a small change. Renting a PAR meter was one of the best things I’ve done when I set up my tank. It would be different in your tank of course but something to look at.

My entire system is 3 gallons, my frogspawn started to expel zooxanthellae after having the lights ramp up slightly past this point. I’m not sure if it was a chemistry or lighting issue but I was happening at the same time everyday until my lighting was reduced. I have a Par meter that I’m going to use later today, I’m hoping to find some answers as I’m lost with these LED light settings.

 

[Cichlid Dad]

It does look to be well under half the original settings. When I backed my Saxby settings down about 10 to 15 percent it significantly lowered the PAR in my tank. From around 250 to 195. Pretty drastic for such a small change. Renting a PAR meter was one of the best things I’ve done when I set up my tank. It would be different in your tank of course but something to look at.

I bit the bullet and purchased the new parwise meter. It has not only par, works in the air, underwater and gives real time light spectrum all in the cell phone. It's a great investment. Look up on googly and check it out.

 

[AstroCoral]

It does look to be well under half the original settings. When I backed my Saxby settings down about 10 to 15 percent it significantly lowered the PAR in my tank. From around 250 to 195. Pretty drastic for such a small change. Renting a PAR meter was one of the best things I’ve done when I set up my tank. It would be different in your tank of course but something to look at.

So my PAR values were terrible, 22 PAR next to my Frogspawn and 25 PAR next to my Stylo. I’m not even sure how the Stylo has survived (has lost polyps on the underside due to the shadowing of the single AI Prime). I ended up ditching the Saxby settings due to how small my reef tank is (I suspect the white light is to blame for the previous issues with zooxanthellae expulsion). I ended up going with the WWC light schedule for their 2.5 gallon tank - it’s very blue so I modified it slightly to have some slight white lighting at the peak of the day. I also reduced the intensity by 25% and will acclimate to the full WWC intensity over the course of a month.

I bit the bullet and purchased the new parwise meter. It has not only par, works in the air, underwater and gives real time light spectrum all in the cell phone. It's a great investment. Look up on googly and check it out.

I’m definitely going to look into this for the future, I don’t have a enough funds currently to take the leap on the Parwise - definitely on my radar for a future purchase though as it looks incredible.

 

[Propane]

I’m glad you discovered your par was so low. Thanks for updating us. Keep us updated on recovery. It was good info for at least me. I’m going to experiment with PAR when I set up my next tank and don’t have corals to see how fast par goes down with reduced settings and try to chart it. I reduced my setting 10 percent and it dropped by 55. I’m sure it’s been done but seems like it would be fun to do it personally.

 

[Cichlid Dad]

Smart Submersible Quantum (PAR) Sensor

PARwise is a unique light meter with the ability to measure spectrum. It can be used underwater and in air. It gives you all of the relevant lighting measurements required to make informed decisions.

www.par-wise.com

Here is the info on the parwise

 

[Propane]

Smart Submersible Quantum (PAR) Sensor

PARwise is a unique light meter with the ability to measure spectrum. It can be used underwater and in air. It gives you all of the relevant lighting measurements required to make informed decisions.

www.par-wise.com

Here is the info on the parwise

Thanks for that. Hopefully it’s cheaper than an Apogee.

 

[Cichlid Dad]

299.00 at brs plus it works on all lighting, and you get a real time spectrum reading