is perfectly acceptable as long as it's accurate. If using a refractometer, shoot for 35 ppt
As for the wrasse, being it's new there is a good possibility it's net/transport damage or it darted into a surface of the tank. Simple injuries like this do not need treating if noticed early enough. Doing a few large water changes with well aged/aerated SW
over the next few days should do the trick nicely. Also be sure the foods fed are soaked in a good liquid marine vitamin before feeding.