Prefinished aluminum oxide.

I'm frankly amazed that furniture with felt pads on the legs leaves scratches on the floor.

Aluminum oxide might be hard and durable but it won't protect from marks. It makes white scratches quite readily and it's not widely used outside of a factory setting.

Your best bet to eliminate this issue would be to sand the floor and use a hardwax oil finish like Rubio Monocoat.

It's not necessarily scratches. It's marks that don't come off.

I did have company once that had a plastic high chair with plastic rollers. That left scratches everywhere.

I have a nylon soft broom. If I sweep and "lightly" rub to get something off the floor, it leaves "sanding" marks.

I've already sanded and put poly in one bedroom but I really don't like the way it looks like plastic laying on top of the wood.

Everywhere that there's a felt pad under furniture legs, there is a round mark. I'm attaching a pic. You can also see a scratch in the floor to the right of the leg marks.

This is 3/4" thick real wood flooring, not engineered. We do not wear shoes in the house or have animals or kids inside.

My hardwood floors were in pretty dull and lousy shape when we had them re-finished. We had our floor people use 4 layers of oil based polyuerethane and they still look beautiful. I know that some people swear by waterbased, but I just don't think it holds up as well as oil..

I used oil based poly in that bedroom.

How do you repair a scratch in poly?

How often have you replaced the felt pads? They can trap grit and turn into sandpaper over time.

GreenDesigns might be on to something. Check the felt pads to see it there's any grit. We use this brand of pad with satisfactory results:
http://www.amazon.com/gp/search/ref=sr_gnr_aps?rh=i%3Aaps%2Ck%3Afloor+d+fender&keywords=floor+d+fender&ie=UTF8&qid=1422967966
For scratches you can use a colored marker to darken light scratches:
http://www.amazon.com/Mohawk-Pro-Mark-II-Touch-Up-Marker/dp/B00AU614WM/ref=sr_1_10?ie=UTF8&qid=1422968051&sr=8-10&keywords=mohawk+marker

The broom thing has me mystified though. Maybe someone with more experience with Waterlox can solve that one. If not here, you might be able to find more info at the NWFA Hardwood Floors magazine website forum.

I've never thought about that. We rarely use the dining room table and the sofas don't get moved. The pads are 5 years old.

I think the WaterLox was defective. I applied it according to the directions and let it dry for months while completing the renovations. The white spots you see next to the chair leg are actually fibers from the felt pads that are stuck on the floor. That's also the reason I think that the broom leaves marks and the floor marks so easily.

Once I sealed the floors with the WaterLox, it was months before we moved furniture in.