Pencil urchin too top heavy?

[droidus]

I noticed at least twice that my urchin was upside down for some time, and I've had to flip him over to get him moving again. Would this algae affect him being able to turn himself over? Is there a safe way to remove it?

 

[shakacuz]

I noticed at least twice that my urchin was upside down for some time, and I've had to flip him over to get him moving again. Would this algae affect him being able to turn himself over? Is there a safe way to remove it?

could be signs it’s dying. has it lost any spines?

 

[Uncle99]

That don’t look right.
What’s water chemistry look like and for how long stable.