Welcome to the patience tests of salt water!! If you have no true inhabitants I would suggest using a table shrimp, though this process can take upwards of 6 months- my 40g took 2 months to stabilize, and then I had a mini cycle when I added my green spotted puffer, got stuck in phosphate. What type of salt mix are you using? Are you wanting a Fish Only With Live Rock (aka FOWLR
) or are you interested in corals and reef?