There is a store here in Wilmington, NC called Pet Supermarket that has a very knowledgeable saltwater staff member, even though they sell no saltwater fish.
We were purchasing RO salt water from one other pet store in the area. Shortly after we were doing regular water changes with their water, we started having terrible nitrate problems (they read 160+ppm on our test). She helped us get our nitrates under control. Turns out that the RO water we were purchasing was high in nitrates. We bought our own RO unit and needless to say, our nitrates are mush lower now.
So, a big thanks to Lee, the manager of Pet Supermarket. Now, convince your boss to allow you to sell some saltwater fish!!!!