Help ID white stringy stuff

[Michael Hagstette]

please help me id this soft, wh8te stringy stuff all over my rocks. Been having some lps problems recently. Not sure if it is related to this or not. Thanks in advance for the help

 

[Ron Reefman]

bump

 

[Justin Cook]

I've had some really thin sponges grow that look similar but it could also be some sort of digiate hydroid. Do they move gently in the tank's flow or are they somewhat rigid? The sponges that I've seen like that have a bit more structure and resisted flow more than a digiate hydroid would.