Tree Sponge- what's the deal?

[Whiterabbitrage]

Everything I've read about Tree Sponges says they are impossible to keep in a tank. Anyone know why? None of the articles explained why.

 

[Calappidae]

Short life span, several daily feedings, algae growing on them, can't expose to air, Very unhardy and the smallest trace of nitrates will kill them, etc etc..