sponge in fuge

my LFS has a very nice looking red ball sponge that im thinking of getting for my Display Fuge. I would put this near the input so it goods good flow. I realize in general that sponges are difficult to keep, but is there any additional issues with keeping one in a fuge. I've seen other Fuges with sponges, but im not sure if special things had to be done.

My fuge currently has Chaeto, some sea grass, and two tube worms. also a 4 inch DSB

 

Should be OK, just make sure that the sponge never leaves the water. It will kill the sponge if air gets in it.

 

yeah be very careful about the air.