White worm-like things in my sump - what is it?

[Acalin]

Hello, all,

First, apologies I am not posting this in the correct sectuon, as I am new here.

I had my RedSea 250 started in January. Waited for about 4 months to cycle and then added 2 clowns, 1 royal grama, few snails, few crabs and a fire shrimp.

All goes well, except that I had a few attempts to turn lights on to prep for corals.
Every time I started to have the brown algae forming and every time I turned lights off to get rid of them.

I finally decided to keep lights on as I want to be over that ugly stage and start adding corals by the end of the year if possible. (Turned lights on about 4 days ago).

Anyway, today, as I was doing the water change and cleaning the filter sock, I noticed some white worm-like stuff in my sump. There are quite a bunch and have no idea how they appeared so suddenly and so many.
I have not added any livestock or anything else (other than rodi salt water, tank buster solution, waste breakdown and algae remover solution and fish fx solution).

Tried to take some pictures and discovered some of them look quite interesting from up close. (Pictures attached)

Any idea what I am dealing with and if I need to take any action against these?

Thank you!

 

[brmreefer]

Pineapple sponges. Harmless filter feeders.

 

[BroccoliFarmer]

Freaked me out first time I saw them. They go away quickly if your nutrients are kept in check.

 

[Acalin]

Pineapple sponges. Harmless filter feeders.

Thank you!