Ok first off I recommend Salifert test kits, or LaMotte but they are more expensive. I simply do not trust those test strips.
You have 300watts of lighting which isn't bad over a 29 gallon tank. However you have a sebae anemone which is 1. a rather touchy specimen to begin with, 2. From almost everyone I have spoken to about them we can almost all agree that they require a Metal Halide bulb to truly thrive.
From the pics, it looks like you may have picked up one of the more healthy of the bleached specimens I've seen normally posted. Bleached anemones are at a high risk because they have lost most or all of their zooxanthellae which they must have to live. It can take several months for them to get this zoo back, but under the proper lighting it can be done.
I suspect that there is some type of acclimation shock if you have only had it for a couple of days. I really can not see the flaking that you are talking about but I would think that it would not be a good thing. I've never heard of an anemone with scales ( a dermatology problem) before.
While in the first two weeks your anemone will be going through many acclimation adjustments. Your water chemistry is one, lighting is another, searching for a prime location (usually the substrate or close by it) It will be spending alot of energy going through these moves.
If it were me I'd take it back and try to get an aquacultured Bubble tip anemone. You would stand a better chance with it. I have tried to help alot of folks with sebea anemones. Unfortunatly after a few months you never hear back from most of those posters, no one likes to post that there anemone has died.
You can:
1. Continue to try and see if you can make this anemone live, and keep me posted.
2. Plan to upgrade your lighting to say a metal halide pendant, for a better chance of success.
3. Try to exchange it for a Bubble tip
4. Play it by ear and let me know how it does.
I do have picture examples of a bleached anemone that was saved and brought back to excellent health if you would like to see them.
Thomas