stuck cycle

Hi all, so I’m cycling my first saltwater tank which has been going for about 4 weeks now. I dosed with Dr Tim’s ammonia to 2.0ppm and added Microbe-Lift Special Blend which my LFS said would help cycle the tank. One week on ammonia was 0ppm, Nitrites rose to 0.5ppm and Nitrates to 5.0ppm...