I have used this exact product. Mine was on new concrete. As stated, prep is the key. Since mine was new concrete, I washed only once but after using the etching acid, I had to rinse several times to remove all the acid residue. I had one helper and basically just kept behind him a little ways with the chips and kept a continuous flow going, if this makes sense. I highly recommend using the chips if only for your concern of a big grey bland floor because it does help as it does look ugly without them (in my opinion). We did mine in about 3 hours and I am extremely happy with it. We did