String white crispy, like an empty tube, covering all rocks

[ReskyZZ]

I have this issue, it was a little only in sump, now spread to all over rock in main tank and start covering coral skeleton,, I tried to clean manually by brush, but after a week it came back with more amounts.. so idk what to do now.. I took sample checked by microscope, it is like tube but nothing inside the tube..

please if anyone can help to solve this issue..

 

[Tahoe61]

Wow, interesting. I don't believe I have seem this one before. I am sure you're not thrilled.

Can you back up and take another image from a little farther away.

Choices are:
1. Sponge
2. Tunicates
3. Bryozoan

I don't think it's a macroalgae.

 

[ReskyZZ]

Wow, interesting. I don't believe I have seem this one before. I am sure you're not thrilled.

Can you back up and take another image from a little farther away.

Choices are:
1. Sponge
2. Tunicates
3. Bryozoan

I don't think it's a macroalgae.

I really don't know what is that, If you say sponge it is not soft.. I attached another picture