You are seeing what we refer to as 'dishout'...and it is a sanding issue. Walnut is very difficult to sand flat. Each of us have a favorite sanding method to get a flat result. I use a machine, similar to a terrazzo grinder, called a Lagler Trio, as the final machine; it never fails in giving an absolute flat result. You will notice dishout and any other sanding anomaly on these dark floors. You will also notice every scratch, dust particle, pet hair and piece of lint.

I have not heard of that brand but we purchased the Bella Cera Ruscello flooring and when the boxes showed up it said the dreaded "Made in China" on them. What could I do at that point? We had it installed and are very happy. There is not one piece in the 1100 sq ft that has a flaw. Now, it has only been a few months, but no problems so far... And we also did about 60 sq ft of LM St Laurent flooring in our vanity area almost 2 years ago, it was "Made in China", which I did not know until later, no problems with it either.

Choosing the right flooring type isn't enough for your living condition. You will have to consider the types of cut: flat sawn, rift and quarter sawn, quarter sawn or live sawn. Quarter sawn and rift & quarter sawn will be best choices, because expansion and contraction is along the thickness of the wood. You will need climate control all year round. 70 degrees at 40 % relative humidity is where you want to be throughout the year. The use of a humidifier/dehumidifier will be needed year round. Although, engineered flooring is more stable than solid. Using the wrong wood specie in your living condition can run the risk of de-laminating with engineered wood. If, the top veneer is more or less stable than it's core and backing. You will experience de-laminating in extreme humidity swings. Take in account of what the engineered flooring is constructed of: mdf or plywood. The width of the flooring will account for how much expansion and contracting also. 2 1/4" strips are the most stable. As you go wider, expect to see more wider seasonal gaps. Proper acclimating is critical, should be performed with a moisture meter. For 2 1/4" strip flooring , sub-floor and flooring moisture should be within 4%. For all other widths 2% moisture differentiation is allowed or should not be exceeded. Don't forget proper expansion gaps, which is the thickness of your flooring, example: 3/4" thick = 3/4" gap. Sub-floor type and condition will affect the performance of wood floors. All this needs to be considered for the proper and successful performance of your wood floors.

I am thinking about using a shellac finish and sealer on this hardwood, which will be the floor for a kid's room. This Bullseye traditional finish and sealer product from Zinsser seems widely used and well liked: https://www.lowes.com/pd/Zinsser-Bulls-Eye-Clear-Shellac-Actual-Net-Contents-32-fl-oz/3449840 This particular product says it is clear, and I think there is an amber tinted version. Can shellac be applied without problems to hardwood? I believe I could put poly on top of the shellac and be done. Is this right? Any tips or warnings? There is also this Sealcoat by Zinsser, which does not appear to be shellac based. https://www.amazon.com/Rust-Oleum-Zinsser-854-Sealcoat-Universal/dp/B000C02BXW/ref=sr_1_3_mod_primary_new?dchild=1&keywords=zinsser+shellac+sealer&qid=1610393849&sbo=RZvfv%2F%2FHxDF%2BO5021pAnSA%3D%3D&sr=8-3 Would the Sealcoat be a better option to just put over the hardwood? I have read elsewhere that shellac can be applied over poly, which is good since I don't know what is on the existing floor. Other places say shellac could be sanded after application, so when we have a chance to completely sand and refinish this floor, I would probably want to do this. Does this sound like an acceptable temporary fix, or is there something I should consider before proceeding? Would shellac ruin or damage the hardwood. I am also thinking about LVP, but I am concerned this hardwood floor is not flat enough for that. I understand the subfloor for LVP must be 3/16" within about a 1 foot diameter to work. Any ideas about this? Is there a way eyeball this floor to determine whether click LVP could be put down? Thanks!