If you are just using fish food I think it will be a long cycle.
You can use a dead supermarket fish dept shrimp. Just throw it in and it will decompose giving you ammonia.
I use pure ammonia to cycle my tanks, seems to go alot quicker. lol
With the fish food it can take several weeks to get enough ammonia built up to kick start a cycle. For more on saltwater cycling check this out
Cycle your salt tank