Here are a few that have lots to offer if you have time.
So Cal Tropical Fish- Fullerton (Chapman)
Age of Aquariums- Signal Hill, CA (Cherry)
Coral Gazers- Tustin, CA (Redhill & Edinger)
Seaside Tropical Fish- Huntington Beach, CA
4 Stores in Orange on Tustin Ave., may as well hit them all they are all within a mile or two of each other.
Amazing Aquariums & Reefs
Pacific Reef
Exotic Fish & Reefs (previously Jeff's Exotic)
New Wave Tropical Fish