Hammer Coral Shrinking

[sailfish1095]

I've had these hammers in my tank for over a year now and recently they haven't been doing well.
No major changes to the tank, other corals (mainly LPS are doing well although the torches seem a little shrunken also)

Parameters (have been stable around these levels for months, testing 2x weekly):
Phosphate: 0.07
Nitrate: 4.0
Ca: 450
Mg: 1380 (this has dropped slightly from around 1400 prev month)
Kh: 9.7
Salinity: 1.026
Temp: 78

Pictures taken about 2 weeks apart.
They are in about 60-80 PAR according to my cheap PAR meter, and flow is not very high - when they were fully expanded they would slowly and gently sway. I see no pest evidence also.

Any ideas about what's causing the decline?

 

[Gumbies R Us]

How is everything else doing in your tank? My guess is they are not getting enough light nor are they getting enough flow

 

[sailfish1095]

How is everything else doing in your tank?

Overall I'd say that everything else (LPS and Soft) is doing ok - most are dividing/growing but also do seem to not be fully extended.

See full view attached, some corals (the acans and duncan on top) had nearly died out months ago but are growing new polyps out of the skeleton so I've kept them in.

 

[Mr. Mojo Rising]

IMO the light is too low. Has any new polyps developed over the year you had it? Over a full year you should have 3-4 new polyps at least on both the hammer and duncan.

Even the green coral on the top right corner - I think they are mushrooms(?) - is reaching for light. The other corals look like they are surviving, but they don't look like they are thriving. You might consider to increase the intensity of the light or upgrade.

 

[sailfish1095]

Has any new polyps developed over the year you had it?

Yeah the hammers were 1 head and 2 heads and both have grown significantly.

I think they are mushrooms(?)

Cabbage Leather

You might consider to increase the intensity of the light or upgrade.

Come to think of it I did drop the white light spectrum (and raised the blues to compensate) about 3 months ago in the midst of severe hair algae outbreak.
These are good points - I'm wondering if the white light drop is now catching up to the corals and I need to adjust things.

 

[Kooma]

I would focus on water quality and not lighting. LPs with too little light will stretch to reach light, too much flow will shrink and the flesh line will rise up the skeleton.

When mine would look like this I would perform a 30-50% water change and vacuum the sand, everything was much happier after.

I’m a believer that we have things we can’t test for that irritate the corals. I’d start here, corals in good water will puff up pretty quickly. I suspect high dissolved organics.

 

[BryanM]

If other things are reaching upwards then you almost certainly have too little light.

I video, posted to youtube, and linked here, could prove helpful for flow.

 

[sailfish1095]

If other things are reaching upwards then you almost certainly have too little light.

I video, posted to youtube, and linked here, could prove helpful for flow.

See:

 

[BryanM]

See:

I would personally add more flow. maybe 50% more.... That looks low to me.

 

[Mr. Mojo Rising]

I would personally add more flow. maybe 50% more.... That looks low to me.

thats my first thought after seeing the video as well

 

[sailfish1095]

Thanks all, I just purchased another wavemaker to run in opposition to the currently installed one (watching the flow I was seeing a large swirling effect even in the "random" mode), will update how that goes.

Any more thoughts on a large WC? I don't want to change too much at once, but a 30 - 40% change seems like it has mostly upsides.