What's in in the overflow?

[Grossman90]

I noticed got this white stuff growing in the overflow of my deep blue. Is this sponge? Im dealing with chrysophytes and not sure if they are the silicate culprit. Thanks

 

[James M]

Need a pic

 

[Grossman90]

Need a pic

lol sorry was testing my water and got distracted. In first post

 

[James M]

Those are sponges...harmless filter feeders

 

[Grossman90]

Those are sponges...harmless filter feeders

Somebody was saying sponge produces silicates. Idk if true. Was reading a chrysophytes thread.