According to a list of latin phrases:
"fere libenter homines id quod volunt credunt" means
"as a rule, men willingly believe that which they wish to"
or
"People believe what they wish to be true, even if it isn't." Attributed to Julius Caesar
Hey, I only know as much about this hobby as the next guy (less actually) but I have done a fair amount of research and the suggestion to let your water 'cure' for 24 hours before adding it to the tank seems to be a little more than just superstition or something I wish to be true.
It is recommended in numerous FAQ's and threads:
http://www.reefcorner.com/Manual/making_saltwater.htm
Also, I have personally observed different refractometer readings from the same bucket of saltwater from when it was mixed to several hours later.
Finally, that white cloud of newly mixed water added to the tank, doesn't look like it would be a lot of fun to 'breath' if you happen to be a sensitive marine animal.
I'm not suggesting that you can't or shouldn't add freshly mixed salt - I merely shared my experience with Clair and she can take it for what it's worth (if anything).
- Chad