When my reef tank needs cleaning I get the crabby pants. It is not my favorite thing to do. In fact it is one of my chores that I avoid like the plague. If you have a nasty reef tank you know what I mean. 
Those crabs can poop a lot and don’t care to clean themselves. Crab poop is not pleasant. As poop goes crab poop really stinks and is sticky. 
Normally you could wait for the poop to dry out thus making it easier to pick up. In a reef tank everything stays wet. The news story is here if you care to see it. 