What is this on my live rock?

[Chowder3]

Hi, so I’m starting over due to a possible contamination. I was removing everything from the tank and noticed these white crystal like things growing on the bottom of my live rock that was sitting on live sand. I’ve done research but I am not sure if this is dead coralline. Anyone know what this may be? Thank you.

 

[SuperReefMonkey]

Maybe sponges

 

[Chowder3]

Thank you.

 

[El_Guapo13]

Do you mean those things I circled in yellow?

Sponges maybe? Did you try poking them to see if they are hard or soft? Did you see how they looked when submerged in the water?

 

[Chowder3]

View attachment 1743179
Do you mean those things I circled in yellow?

Sponges maybe? Did you try poking them to see if they are hard or soft? Did you see how they looked when submerged in the water?

Hi, yes those things! They are as hard as the rock it’s self. They look exactly the same under water.

 

[El_Guapo13]

Hi, yes those things! They are as hard as the rock it’s self. They look exactly the same under water.

Hmmm.... might not be sponges then.