Is shading BS?

[madweazl]

I've seen a number of posts regarding LEDs and the shading issues they create that lead to STN at the base of corals. The notion seems crazy to me because many of my SPS grow in areas of almost no light without demonstrating this behavior. It seems to me there has to be something else that causes this or is exacerbated by the lack of light instead of purely a lighting issue. One of the videos by Triton showed corals that were growing well on the undersides, out of light as well.

The frags in the picture below are only three to four inches in size but have extremely heavy shading; the one of the left is illuminated by a Kessil mounted to the right of it, so there is heavy shadowing cast to the left of the coral; it actually has more growth in this area than anywhere else. The one on the right grew down and behind a ledge that protrudes roughly 3/4" outward (toward the viewer). I have a pikachu that has grown well into a crevice/cave in the rock that couldn't receive less light unless there were none.

Any theories on the root cause? Am I crazy? These are just frags, you don't know what you're talking about? Any other thoughts?

Edit: The only adjustments made to this image were exposure, white balance, and lens correction; no contrast, no saturation, nothing else.

 

[saltyfilmfolks]

Shading can cause die off. My stylo has some Lower in the branches, but I do have an acro that has new branches growing deep in the shade too.

But I’d also Agree some folks blame shading for a number of maladies.

 

[madweazl]

Shading can cause die off. My stylo has some Lower in the branches, but I do have an acro that has new branches growing deep in the shade too.

But I’d also Agree some folks blame shading for a number of maladies.

I just don't know, I literally have an SPS that is growing into a cave that receives zero direct light and an extremely low level of ambient light. It just seems like there has to be something else at work, too.

Edit: one thing I will add is that I dont use filter socks and I feed heavy (LRS Reef and Herbivore Frenzy). I add nothing else to the tank (i.e. phyto, reef roids, etc.). You can see there is quite a bit of stuff suspended in the water column in the original image I posted. Does that make a/the difference?

 

[saltyfilmfolks]

I just don't know, I literally have an SPS that is growing into a cave that receives zero direct light and an extremely low level of ambient light. It just seems like there has to be something else at work, too.

I agree. Even if the light bouncing back is less then 100 par (Highly unlikely) that still shouldn’t allow growth.

A lot of folks do have like a single kessil too low with black sand. An yea , that could be a prob. But I’d still look at other issues beyond shading.
Esp if that means automatically buying t5 to stop the shading. Lol.

 

[Triggreef]

Those are small frags. I would venture a guess in a year or 2 the bases will have died, unless it grows out faster than the tops. But in those pictures you can already see the lack of pe on the base of those acros. IMO that is because of the lack of light in that area. Nothing else is different. Same water, same flow, different light.

My bigger colonies as they branch out and shade out the base, the base dies. Its not like I have smaller frags of the same that the base is dying even though its in light.

 

[madweazl]

I agree. Even if the light bouncing back is less then 100 par (Highly unlikely) that still shouldn’t allow growth.

A lot of folks do have like a single kessil too low with black sand. An yea , that could be a prob. But I’d still look at other issues beyond shading.
Esp if that means automatically buying t5 to stop the shading. Lol.

I actually have black sand LOL. The coral on the right actually did great in 105 PAR (pictured below) and the color was actually awesome (green growing edge that disappeared with higher PAR). While I dont have anything capable of taking readings under those ledges and under the corals due to size limitations of the sensors, I'd guess they're well below 50 PAR.

 

[saltyfilmfolks]

This one is bout five inches
https://www.reef2reef.com/threads/hey-acro-heads-heres-a-head-scratcher.336392/

 

[LobsterOfJustice]

Shading concern is real. I have 3x kessils over a 180 and several large sps colonies. After about a month you could see clear cut crisp lines of die off on the corals where shadows were cast. I installed 4x T5 to help with the issue. I am also in the process of installing a light mover.

It’s not the same as corals growing in indirect or diffuse light, and you won’t see the effect with frags or small colonies. The corals in the pictures you have posted are small enough that a light source far from them will still evenly light them. You begin to see the effect when Cora’s get large enough to have multiple tiers/layers and upper branches cast shadows on close nearby branches. A source of shadow closer to the coral (such as upper branches a few inches away at most) casts a much harsher and sharper shadow than something farther from the coral and closer to the light, which just results in diffuse indirect light (but still relatively even).

 

[madweazl]

This one is bout five inches
https://www.reef2reef.com/threads/hey-acro-heads-heres-a-head-scratcher.336392/

Thanks for the link, Dana always has some interesting data.

 

[madweazl]

Shading concern is real. I have 3x kessils over a 180 and several large sps colonies. After about a month you could see clear cut crisp lines of die off on the corals where shadows were cast. I installed 4x T5 to help with the issue. I am also in the process of installing a light mover.

It’s not the same as corals growing in indirect or diffuse light, and you won’t see the effect with frags or small colonies.

I get that you've observed this but can you say it was a direct result of the light?

 

[Flippers4pups]

There's some light reflection that happens off the glass, water breaking the surface would refract some light in different directions.

If a coral is growing into a shaded area, but the main body is receiving direct light, the tissue in the shaded area will still receive energy through photosynthesis, but there's a tipping point to that.

@saltyfilmfolks, I haven't read that link yet.

 

[LobsterOfJustice]

I get that you've observed this but can you say it was a direct result of the light?

Absolutely. I’m saying you can see crisp lines of die off exactly where crisp lines of shade/shadow fall onto the coral.

Sorry, was editing my original post with additional info as you were relying.

 

[madweazl]

To add a bit more information, an A360WE is centered about two inches to the right of the acro on the right of the original image. Light schedule is on a parabola that starts at 11% (when my controller actually fires the Kessils) and peaks at 60% intensity six hours later (12 hour photoperiod). PAR at 60% intensity directly under the light at the same depth, is ~250; the coral on the left in the original picture would receive a fair bit less but is in an area I cant effectively measure because of the canopy.

 

[LobsterOfJustice]

Here is an old picture, best I can dig up that shows the effect. You can see the section of upper cap casting a pretty clear shadow on the lower section. I think I had installed the T5s at this point and the area has started to color back up and recover.

 

[madweazl]

Here is an old picture, best I can dig up that shows the effect. You can see the section of upper cap casting a pretty clear shadow on the lower section. I think I had installed the T5s at this point and the area has started to color back up and recover.

Any guesses as to why the "branch" below it didn't suffer the same fate?

 

[chefjpaul]

since coral, when they "reproduce" are exact clones.

These clones have genetically identical codes and zooxanthellae living within are accustomed to a certain living condition / environment, (atoll, lagoon, fringing) etc... even within the same species, that possibly migrate in current.
They just "know" genetically what they need, or are used to, from the host.

Kinda what Dana was reffering to in Saltyfilmfolks post/ link.

The zoo just know.

No doubt there is shading with led compared to other sources, but we need to have a serious discussion with each and every zooxanthellae member and host coral prior to purchasing. We should have them fill out paperwork / questionnaires regarding their enviromental history along with records of their previous parameters. These questions will help us a lot I assume.

 

[Rakie]

A lot of folks do have like a single kessil too low with black sand

LOL -- You just summed up like 40% of new reefers. Gotta keep that kessil 2" off the water !

 

[madweazl]

LOL -- You just summed up like 40% of new reefers. Gotta keep that kessil 2" off the water !

Mine are 5" off the water

 

[saltyfilmfolks]

since coral, when they "reproduce" are exact clones.

These clones have genetically identical codes and zooxanthellae living within are accustomed to a certain living condition / environment, (atoll, lagoon, fringing) etc... even within the same species, that possibly migrate in current.
They just "know" genetically what they need, or are used to, from the host.

Kinda what Dana was reffering to in Saltyfilmfolks post/ link.

The zoo just know.

No doubt there is shading with led compared to other sources, but we need to have a serious discussion with each and every zooxanthellae member and host coral prior to purchasing. We should have them fill out paperwork / questionnaires regarding their enviromental history along with records of their previous parameters. These questions will help us a lot I assume.

Yup. As I started to dig in and read more and more of the research Dana has provided, it’s really complicated from coral
To coral. Particularly weird when dealing with Coral that have been half killed (repeatedly , by me ) .

 

[chefjpaul]

Yup. As I started to dig in and read more and more of the research Dana has provided, it’s really complicated from coral
To coral. Particularly weird when dealing with Coral that have been half killed (repeatedly , by me ) .

You two have me on the quest of 2018, to understand the lighting aspect better, in more detail of, since currently the water seems stable, need a subject to focus on that I lack understanding.