White crystal on rock?

[LonitzCMU]

Hey All,
I am new, my tank has cycled, I added fish and everyone is doing well. Water parameters I check today were still great. But I am starting to notice brown algae (which is fine, I added snails) and some white crystal like material on my rock. Im wondering if anyone can identify the white Crystal like stuff on my rock. There is also a white stringy substance on the one, but not on the others

 

[Jaebster]

venturing. I cant answer your question...
But...
Welcome to R2R!

 

[Greg P]

Could be some sponge
Touch it. Is it gelatinous and falls apart, or is it soft but a solid mass?
Solid mass is most likely sponge. Gelatinous is probably some bacteria and will go away if you scrub it off with a toothbrush and scrub the rock under it.