More inverts?

[Proseph]

I have a 1 year old 29g biocube mixed reef.
Currently I have
1 ORA clown fish
1 clown goby
1 neon goby
1 royal gramma
1 tail spot blenny
1 pom pom crab
2 Astrea snails

Due to fine sand, I cant point my power heads directly at the sand to keep detritus off of it. For this reason I have decided to buy a Tonga fighting conch.
However I would also like to add 4 sexy shrimp, 1 emeral crab and 1 Tuxedo urchin.
Am I currently running the risk of over stocking? I cant imagine sexy shrimp or a emerald crab producing much waste, though I might be wrong.
What does everyone think?

 

[TL1000RSquid]

Sexy and emerald will add nearly nothing to your bioload, I don't really know much about urchins so I won't comment there. I'd probably consider adding a few more various snails though, cerith, nassarius.