Chopped urchin?

[zenn]

I've got a pencil and purple(spiney) urchins in my sump/fuge. They are in the fuge section currently and cannot get to the return pump compartment. But i've got quite a bit of coralline algae growing in the return pump area and it's kind of worrying me as far as the pump's mechanical health is concerned.

So i was wondering if i put the urchins into the return pump compartment they'd not only love to eat all that coralline algae but they could also help me clean it up in there. I have a Mag 9 with the cage guard around the inlet but there's spaces in between the guard bars. I don't know if the urchins would climb in the guard and possibly get stuck in the pump or not but it worries me. The urchins don't look small enough to get into the pump but i guess you never know.

Should i let them loose in the return compartment or let it be?

[zenn]

so no worries? Urchins can't crawl into tight spaces?