White strings

[Jason Jones]

im not sure if this is the right section but I’m trying to figure out what this is.
It is growing on the bottom of my frag racks, in the skimmer and return section of my sump and around the skeleton of some of my LPS.
I’ve been removing from my corals but there is a good amount in the sump now and I don’t know if I should be concerned.
Thanks in advance.

 

[Maggie321]

Pretty sure that's a type of sponge. I have some small ones in my tank

 

[WWIII]

Pretty sure that's a type of sponge. I have some small ones in my tank

That would be my guess as well. Pretty wild looking little things!

 

[Jason Jones]

It is a soft stringy structure that seems to withdraw or retract once it’s out of the water.
It has a strong grip on the acrylic and does not come off in mats.

 

[reef lover]

I second a type of sponge.

 

[Jim Fox]

I'm going with sponge as well.

 

[Jason Jones]

Thank you.
I had assumed it was harmless, but I wanted to double check.