Help id this brown thing

[miserkris]

Whats these brown stuff growing all over my dt?

 

[ZANYMASTER]

Looks like brown diatom.

 

[miserkris]

I dont think its diatom,
This has distinct rings and its same size, its every where.
Its very hard when touched....see pic..
What is this, good or bad, its spreading.
Thx

 

[ZANYMASTER]

Can you get us a better bigger pic if you can?

 

[skene]

http://www.melevsreef.com/id/

 

[noodleman]

vermetid snail

 

[daaznmofo]

what noodleman said