help with clean up crew for my 28 gal. reef ?

[ed102475]

Hello and as the topic says i need help with my clean up crew.
I am starting over after about a year away.
It has be set up only about 5 weeks.

EQUIPMENT =

28 gal. with 5 gal. sump

T-5 lighting

100wt heater

20 lbs. live rock (getting more)

40 lbs. live sand

LIVE STOCK =

1 Royal gramma

6 Margarita Snails

1 Mexican turbo snail

12 hermit crabs

Should i get a brittle star my LFS told me they are not safe,
or any others that may help my tank?