Why do I get this bleaching?

[Kris 2020]

I have had this birds nest for over a year. It keeps bleaching from the bottom up, then I frag off the healthy parts (which involves lots of bad words), end up with a mess of frags. I will take a nice one and find it a home in the tank. It grows like mad. Then it starts bleaching. I swear it’s still growing as it’s bleaching. I’ve done this like 4-5 times since I got the thing. My other sps looks fine….it will be lighter in color in the areas that do t get as much light but still will have some polyps in those areas. Tank is 10-12 years old. Last testing was 10-16:
temp 78.6
ph 8.13
nitrate 3.7
phosphate .03
alk 8.4
calcium 392

i only test mag and potassium occasionally but last check was 1395 mg and 440 k. These are all typical results for me. I think I turned up the calcium dose a bit after this test. I feel like I’m always doing that!

 

[guylaga]

Thats par for the course with birdnests, once it has grown large enough to shade the branches underneath they will start to die off.

Only way to avoid it is to frag as you go so that light is still reaching the lower branches, or frag of the lower branches when they are still alive.

 

[Uzidaisies]

I have no idea. It reminds me of white band, but that’s only found in Acroporid corals from what I read.

 

[Uzidaisies]

Thats par for the course with birdnests, once it has grown large enough to shade the branches underneath they will start to die off.

Only way to avoid it is to frag as you go so that light is still reaching the lower branches, or frag of the lower branches when they are still alive.

That’s kinda what I was thinking but I didn’t know if that happened or not. Thanks for the info!

 

[LiveFreeAndReef]

It's die-off because it's getting shaded out. Time to frag and re-glue!

 

[vetteguy53081]

Looks like shading (where light is blocked by branches above). Other causes are:

Low Magnesium
Low calcium
Alk too high
Salinity too low
lack of water flow to that area.

 

[Kris 2020]

Thanks everyone! I’ve just always wondered about this, and I was dreading fragging it AGAIN thinking why does it keep happening to this particular coral. Good to know it’s par for the course. I’ll have to be better about “pruning” it from time to time.