Birdsnest bleaching - alk swing and nitrate depleted?

[Northern Flicker]

What would be your guess for this bleaching event - interestingly, it’s only happening to my teal birsdnest - multiple mini colonies spread across different areas of the tank.

3 potential causes:

1. 2 months ago I went from T5+2 Primes to T5+2 Primes+1 Hydra 32, effectively doubling the LEDs. I did turn down the intensity but it’s still a lot of light.

2. I had my alk swing from 8.2 to 6.4 over the course of about 10 days. The bleaching started around the time the alk crashed downward. This is my guess, although this coral has been bulletproof in the past.

3. Nitrates have consistently hit 0 until just this week when I started dosing diy calcium nitrate to maintain 10ppm. Bleaching occurred before I started dosing when nitrate hovered between 0-1.

The interesting thing Ive never seen is that the polyps are still extended but they are white. When I think of bleaching, I think of an STN style event.

In some of the pics below you can see Acros and montis which are not showing any stress signs.

Relevant params:

Alk - 7.4-8.0 maintained by AFR
SG - 1.026
P04 - steady for months around 0.13
Nitrate - usually 0ish, now holding around 10ppm
Cal - 450
Mag - 1400
pH - 8ish

 

[ChrisfromBrick]

both the Alk swing and the Nitrate of 0

 

[Dburr1014]

What would be your guess for this bleaching event - interestingly, it’s only happening to my teal birsdnest - multiple mini colonies spread across different areas of the tank.

3 potential causes:

1. 2 months ago I went from T5+2 Primes to T5+2 Primes+1 Hydra 32, effectively doubling the LEDs. I did turn down the intensity but it’s still a lot of light.

2. I had my alk swing from 8.2 to 6.4 over the course of about 10 days. The bleaching started around the time the alk crashed downward. This is my guess, although this coral has been bulletproof in the past.

3. Nitrates have consistently hit 0 until just this week when I started dosing diy calcium nitrate to maintain 10ppm. Bleaching occurred before I started dosing when nitrate hovered between 0-1.

The interesting thing Ive never seen is that the polyps are still extended but they are white. When I think of bleaching, I think of an STN style event.

In some of the pics below you can see Acros and montis which are not showing any stress signs.

Relevant params:

Alk - 7.4-8.0 maintained by AFR
SG - 1.026
P04 - steady for months around 0.13
Nitrate - usually 0ish, now holding around 10ppm
Cal - 450
Mag - 1400
pH - 8ish

These are new pics?
Where's the bleaching?

 

[Northern Flicker]

These are new pics?
Where's the bleaching?

The red boxed areas, the tips mainly on each colony, were all teal a few weeks ago and would have matched the non-highlighted areas.

Historically the growth tips on these colonies have only been white on the very end for me, not turning the whole limb white.

Interesting that the main bodies are staying coloured up. The PAR must be about the same 1/4" away, and their flow hasn't changed in 5 months.

 

[Dburr1014]

For reference:

My birdsnest is recouping from an almost full fallout.
Alk has dipped in the past and nitrates always read 0.
I run alk at 8ish, Monday it was 7 and corrected it over 2 days. It has been down to 6 a month ago. I need to adjust the calrx but I'm waiting until after my trip next week.
The fallout I'm 90% sure was lack of flow because of fast growth.

March 2024 (on the left)



May, on the right. (new tank)
Looks horrible.



Recent Pic last week. Starting to fill in.




I have a bunch of fish, 12, two more coming out of qt tonight.

Feed them, they feed the coral.
N and P come from them.
I had a hard time dosing nitrate, lots of cyano.

Could be lights, are they set to where they were or did you just add gobs of par all at once?

Yours don't look like stn but growth. The flesh has to catch up is all.

And alk going down with no3 down is better than alk going up with no3 going down.

All in all, I don't think you have any problems here.

 

[Dburr1014]

The red boxed areas, the tips mainly on each colony, were all teal a few weeks ago and would have matched the non-highlighted areas.

Historically the growth tips on these colonies have only been white on the very end for me, not turning the whole limb white.

Interesting that the main bodies are staying coloured up. The PAR must be about the same 1/4" away, and their flow hasn't changed in 5 months.

So it's all the branches facing the light.....



I don't think there's a problem.