What are these things that are starting to appear everywhere?

[ItsAName]

I noticed one hanging down, then as I grabbed the flashlight and looked around I saw them everywhere. Maybe 4-5 dozen throughout the tank.
My first thought are sponges, but I haven't had sponges in nearly two years and the last time I had them I literally had thousands appear in my refugium. I hope that's not happening in the display! Also, if they are sponges anything that may have caused an outbreak and any way to slow it down?

 

[Flippers4pups]

Pineapple sponge. Filter feeders. Good guys!

 

[squaretwelve]

Look like pineapple sponges, especially the first image.

 

[Hemmdog]

Yep pineapple sponges. Are you using RODI water? They feed on silicates. Do you have diatoms as well?

 

[ItsAName]

I am using RODI but just replaced the filters, maybe they were getting old. No diatoms luckily. I disturbed my marine pure in my refugium recently, do you think that would have done it?

Also, I was getting cyano and used chemiclean too, but never got sponges after that before. It's my third time using it in 2 years.

 

[vetteguy53081]

Not pineapple. Looks like cryptic sponge

These are pineapple:

 

[CasaReefer]

Not pineapple. Looks like cryptic sponge

These are pineapple:

So is that Good Or Not so Good?

 

[vetteguy53081]

So is that Good Or Not so Good?

All sponge are filter feeders which is good BUT this type can be evasive. Cut back or pull off if you don't want them in tank.