Grit series is crucial when it comes to sanding a hardwood floor.
You should begin with a coarser grit and work your way down to a finer grit. The first grit is used to remove any finish, the second grit is used to smooth out the first grit's pattern, and the third grit is used to remove any residual sander marks and add the finishing touches.
You won't be able to achieve a smooth transition between grits if you use the wrong sander series. A grit line would be left behind by your big unit, which you certainly don't like.
You can achieve a cool, smooth transition from one grit to the next if you choose the right sequence for the floor you're working with. The finish will adhere uniformly to the floor and look fantastic.
To achieve a smooth sanded floor, you can need more than three grits. Most floors only need three passes with the big machine to achieve a smooth finish if you follow the proper sanding series. Checkout the best Floor sanding in Adelaide for more info.