ID Please

[bangbangkhan]

i have something like a snail living in my refugium...i don't know if this is a pest or not.

The third pictures are of i think copepods? because they are not moving...are they empty shells?

Thanks

 

[Sugar Magnolia]

The first two are stomatella snails, beneficial. I can't really make out what the third pic is on my phone...possibly scypha sponges.

 

[bangbangkhan]

thanks! are scypha sponges beneficial too?

 

[Monkeyfish]

thanks! are scypha sponges beneficial too?

Harmless filter feeders