Beginner Looking for stocking advice-FOWLR-30g

I started my thread over at another forum but you guys seem a little more active in the marine section :)



Cliff Notes:

30 gallon tank

fluval 206 cannister(I know...I Know...it is being cleaned bi-monthly)

30lbs live rock

30lbs live sand



Has been up and running about two months, started cycling with the live rock and sand, added a dead shrimp for good measure. Never got a nitrite spike, got ammonia and nitrates through the roof and it has since read zero ammonia for about a month or more now. Nitrates in the 5-10ppm range.



Current stocking:

six line wrasse

banghai Cardinal

1 peppermint shrimp

2 snails

A scallop hitchhiker



Questions:

I'm going to the fish store tomorrow to pick up some more live stock, i'd like to get a couple more snails, and a few more peppermint shrimp. I also need something to clean my sand with, what would work well for that?



My wish list of fish is a black/white clownfish, and I'd love a flame angel but I have concerns about the aquarium size. Live aquaria used to indicate a 30g was fine but has since upped it-what gives?



I know I need to stop the stocking of fish at 4-5 and that is fine with me, I just really want the other two fish to be active, unique looking, colorful fish(i know black and white clownfish doesn't meet colorful, but they are really cool looking!)



Throw some thoughts at me!



Thanks,