What is happening here?

[itz frank]

Radion gen3 rw30. Not stn or rtn. Polyps just not extended and white skin.

 

[SoloGarth]

What is happening here?

Looks like tissue recession to me. Is that algae growing up against it?

Could also be some localized bleaching/lightening due to shading.

 

[itz frank]

It brushes it in the flow. Could it be from shading?

 

[SoloGarth]

Yes if it is in shade. I would remove that algae though either way.

 

[itz frank]

And this is why I hate my radions.

 

[SoloGarth]

Why? I have radions. Also that same coral. No similar problem.

 

[SoloGarth]

Ignore the cut sections. Those are from taking frags.

 

[SoloGarth]

Since the top looks fine I would think that the algae might be irritating or harming that frag. Algae and corals have methods to compete with one another.

Could also be high PO4 or NO3.

 

[itz frank]

I just did 3 25% wAter changes to clean the water column.

 

[SoloGarth]

Have you measured your parameters? In an SPS tank in particular you really want to remove as much algae as possible. Manual removal in addition to nutrient removal.

 

[itz frank]

The algae you're seeing is bryopsis. I'm working on it.