Tank Cycling Problems

[MMAX]

Ok, not like I'm new at this or anything like that, I know cycling takes time but.....Tank was filled with RO/DI water and Instand Ocean salt on Feb 7. Added my live rock which was in a Rubbermaid tub and cured on Feb 13. Tested ammonia the next day and it was 0.2ppm. On Feb 17 ammonia was 0. Put in a hermit crab and 3 serpant stars out of my 20gal on Feb 25, ammonia was 0.1ppm. Feb 27 ammonia was 0.05ppm, threw in a trochu snail from my 20gal. All was fairly good until Mar 7. Added 6 more trochus. Mar 11 ammonia was 0.2ppm. Mar 12 to 17 ammonia staying around 0.2. Mar 18 it was at 0.3 and today still at 0.3. Is it just me or should the ammonia levels be dropping by now? I've cycled a few tanks in my time and they never took this long. Anything seem wrong or am I doing something wrong?