Hi Sandy,
No they are not the same. ro/di is purer than distilled. If you don't believe me, try drinking a glass of distilled water, then they drinking a glass of ro/di.
Forget what the manufacturer says about calibrating with distilled.
Pick up some Pinpoint 53mS calibration fluid and adjust your refract to exactly 35 ppt or 1.0264.
The stuff is cheap and will insure your refract is calibrated accurately for salt water.
Hope your Holidays went well.
And you should remind Ed that the woman in the house is aways right.
