refractometer calibration confusion

[SWCC]

OK, I have read all I can and still find myself confused. I have a DD H2Ocean seawater refractometer(says 20c calibration temp). I an slightly confuse at using pinpoint solution to calibrate. Do I use the pinpoint solution at my normal room temperature(about 72 deg year round) and set refractometer at 35ppt or do I need the refractometer at 68deg to calibrate the pinpoint solution correctly?

 

[Boomer]

Yu can cal it at any normal room temp. It DOES NOT have to be cal at 68 F

 

[SWCC]

thank you.