There is a place in Shelby Township called Kee's Aquarium & Pets, it is family owned. They have good variety, as far as price they are probably not the cheapest in town but they are good when it comes to customer service.
Number - (586) 739-9140
Dave is the owner I would speak to him or Jason, they are both knowledgeable when it comes to Salt Water.
Probably would take you about 30-40 min. from Detroit.