uneven SPS coloration

[hayabusa2003]

I accidentally broke a few branches off of my Digis while cleaning, and I noticed that for those branches that started growing more horizontal, the underside of the branches are brown. Same goes for my green/purple rim cap...it's starting to develop whirls, but since the whirls overlap and are shadowing the whirls underneath it, the polyps are not as green as the rest of the colony. You only see the brown side of the SPS if you kneel in front of the tank and stare at it in certain angles...which I do daily I repositioned the digi and the brown side is now colored up, but I assume the reverse side is browning out..

So how to get more even coloration? I don't think increasing my lighting will help, since even if I went 400watt MH, the shaded branches will still be shaded. I figure it's something to do with my water chemistry?

On a side note, my blue tort and tyree birdsnest grows very upright, so their coloring is very even. Digis don't grow as vertically in my experience.

 

[jazzsam]

Increasing your light will not help if different parts of the coral are exposed to more/less light. It will always be a little different becuase the shadows are always in the same place. This is why the sun coming up and going down would be better in nature because it hits different parts of the corals. you light is always coming from the same direction.

 

[MikeNapoli]

How old are your bulbs ... you might need to change them.

 

[hayabusa2003]

How old are your bulbs ... you might need to change them.

I guess it could be my bulbs...just doesn't really make sense to me. I have new bulbs coming this week, guess I'll see soon enough. My bulbs are 6 and 11 months old (bought used retrofits that's why the age is so different). I run 2x15K Iwasaki's 7hrs a day.

What's a good rule of thumb to tell when a bulb is past it's prime?

 

[Phyl]

The bottoms of all corals are typically less colorful than their well lit counterparts from the same coral. That's perfectly normal. I'd suggest a different lighting strategy before I'd suggest changing your bulbs. I don't think that's going to help any.

 

[mladencovic]

How old are your bulbs ... you might need to change them.

I guess it could be my bulbs...just doesn't really make sense to me. I have new bulbs coming this week, guess I'll see soon enough. My bulbs are 6 and 11 months old (bought used retrofits that's why the age is so different). I run 2x15K Iwasaki's 7hrs a day.

What's a good rule of thumb to tell when a bulb is past it's prime?

As previous posts have said, the light of different intensity will produce different colors, where brownish will be correspond to lower light. If certain piece of coral is in shade, it will not color fully. MH with their very small surface area of the light orign will produce very directional and focused light and will easily create shaded areas with higher contrast between light and dark areas (but it will also produce nice shimmering effect). T5s and PCs have much larger surface are of the light source resulting in more difused and less directional light, and are usually placed to cover tank wrom different angles resulting in more uniform light coverage of corals. Of course underside of the coral plates and branches will never have the same amount of light no matter what you do and will therefore hav different coloration or doscoloration.

 

[hayabusa2003]

thx. I understand that MHs have narrower broadcast, which is why reflectors are so important. I have a diy reflector from hello-lights. I also supplement my lighting with 4x96watt PCs (2 actinics and 2 67Ks).

The discoloration seems to be specific with certain colors. My green digi is brown on the undersides, but my orange digi right next to it is well colored all around. Could too much surface agitation diminish my light quality? I have alot of water movement at the surface to help with gas exchanges.

 

[rutz81]

This happens on many of my SPS in my tank. Although, adding sand to my tank helped this a little since the white sand plays an almost mirroring effect and shines minimal amounts of light upwards threfore somewhat coloringt he undersides. But, it is still no where near the color of the top.

 

[Chris Jury]

Agreed, this is caused by self-shading and a fixed angle of lighting. It's not harmful per se. Reflective (white) sand can definitely help. Other than that one would really need to move the position of the lights (e.g., with a light mover) which isn't the most practical most of the time.

cj

 

[concept3]

i don't have sand to reflect the light back up, so I plastered a whole bunch of heavy duty aluminum foil underneath the tank. It worked out great, but there are still some duller spots which are normal-