New tank help??

[daplatapus]

When I started my reef tank (77 gal) I put in 100 lbs of tonga live rock from my lfs. Rock was out of water maybe an hour or so. Started ghost feeding the tank for the first few days - no ammonia. Threw in a cocktail shrimp - waited about 2 weeks. Cocktail shrimp completely dissolved and disappeared - no ammonia. I never did see any spike of any kind in my tank.
My only slight concern about your situation is the re-used sand. Actually it's not the sand in itself, it's the detritus that accumulates in it over 2 years. If you rinsed it well and are not reading any NH3, NO2, or NO3, I would suspect you won't see any cycle at all.