White egg looking cocoon weird algae??? Help me

[LuisLpz01]

Hey, been in the hobby for a couple of years and recently about a couple months ago this started to pop up and I have no idea how to stop it or what it is. Is it bad? Good? I don’t know seems to only be in dark areas like filters and sump area nothing in the display. I have a saltwater tank with coral and fish.
Thanksss

 

[WheatToast]

Pineapple sponges (Sycon). Harmless filter-feeders and common hitchhikers.

 

[ReefRondo]

Pineapple sponges. Great filter feeders however can be a sign of high nutrients and silicates.

 

[WheatToast]

Pineapple sponges. Great filter feeders however can be a sign of high nutrients and silicates.

Not sure about silicates, as these are calcareous sponges, though they are definitely neat organisms to have around in my opinion.

 

[ReefRondo]

I was always under the impression sponges were associated with excess silicates. I've read it multiple times however that doesn't make it the truth.