I'm not sure how to make the temperature conversion. Also, 1.02x refers to SG. Salinity is in parts per thousand, or ppt.
Salinity will not vary with temperature swings, while SG will vary with temperature.
I wouldn't go with the recommendation on the salt mix for a reef tank. It's pretty well accepted that your salinity should be at 35 ppt these days.
Also, when testing SG, you also need to determine at what temperature your hydrometer is calibrated. Some will automatically adjust for temperature changes, like the Coralife Deep Sixx. Others will require some conversion.
If I recall (and I know someone will correct me if I'm wrong), for each 5 degrees upward change in temperature, your SG reading will vary by -.001 assuming constant salinity. So the salinity with an SG of 1.023 at 75 degrees F will be equivalent to the salinity with an SG of 1.022 at 80 degrees F, etc.
Look for a salinity of 35 ppt.
Here's the conversion table for salinity to SG.
http://www.reefs.org/survey/salinity_conversion.html On the chart, find your temperature, look across and you'll see 34.9 ppt salinity. That corresponds to an SG of 1.024 at 82 degrees F.
Anyway, HTH.
