Bleached rock. What's this?

[zoalander1]

I used bleach to cure some rock. I went with 1/10 bleach to water. Sat for a week. I noticed some rocks have this white crust over them. Not all the rocks have it. Maybe 1/3. I hit it with my water hose and some seemed to chip off. Anyone know what it is? Should I scrape it off? Is it safe to put in the tank? FYI I'm not done with he rock. Going to let it sit in the son for a few days then will use some dechlorinator and let them soak for a few more days

 

[zoalander1]

Maybe dead algae?

 

[Tahoe61]

I am guessing but dead Corailline algae.

 

[zoalander1]

I am guessing but dead Corailline algae.

That was my first thought but the rock had only a small amount of coralline

 

[zoalander1]

Any other ideas?