For a 125 gal
tank 45 lbs may not be enough to jump start your cycle. The .5 ppm
isn't as high as I'd prefer it for a good cycle but it could have been slightly higher on Fri or Sat. Are you getting any no2
readings at this point? IMO
it couldn't hurt to add at least 1 or 2 good sized shrimp to get your nh3
closer to 2-3 ppm
Alternately since you have such a large tank you could stock it very slowly once your cycle is done to give your tank time to build up bacteria.
Everything else is fine at this point.