hi. how long has the cc been in the tank? if it's not very long, you might not see any algae outbreak. the algae comes from stirring up the detrius in the crushed coral while removing it. if there is no detrius, there will be no algae bloom.
also- i'd purchase dry aragonite based sand, instead of "live" sand. the only difference in the two is that the live sand has some bacteria in it. your tank is already cycled. you don't need to spend the extra money on live sand. it's a common misconception that people(not necessarily you) believe that they are going to get alot of visible living creatures in their bag of live sand. this is not accurate. it's just some bacteria.
with a flame hawk shrimp might not work. they say they have been known to eat small inverts, but i would assume that's up to the individual fish. it would really stink to find out on a 20 dollar shrimp.
also, i've seen sally lightfoot crabs sit on rock ledges and lunge at fish as they swim by.
some have good luck with them, but i use the general rule that anything with alot of armor and sharp pinching weapons attached to their bodies, have the predatory instinct.
back to your question- some like snails, some like hermits...some like a few, some like alot.
you need to decide what is best for your tank. there is no set rule. i have about 20 snails in my 195 gallon display. i don't have algae issues because i keep the water clean.
a friend of mine has hundreds in his 75 gallon tank.
i would add a few of whatever you like, and see how it goes...add more if you need or want to....
the powerhead you mentioned- is it a maxijet 1200? if so, i'd add about 3 more of those in different areas of the tank.
