I found this info searching google from a redsea rep.
"Ok Folks, A little Clarification, the suggested mixing instructions are for our Red Sea Coral Pro salt, you can also use them for our Red Sea salt, we are certainly not suggesting these instructions work for our competitors salt.
Our Coral Pro is pretty unique in that is has probably the highest biologically balanced levels of Foundation Elements in any salt available today, the latest formulation coming from the research undertaken developing the Reef Care Program.
It is important to mix at the desired tempreture (20 oC/68 oF) and for the mentioned duration ( as soon as mix is clear usually 0.5 hours to 2 hours but no more than 4 hours) as we are very close to the natural precipitation levels on some of these elements, mixing for longer periods of time and using aeration can drive off more Co2 raising the pH and alkalinity resulting in enhancing the possibility of precipitation, once this precipitation if formed it will not dissolve quickly as it has become Calcium Carbonate.
I have been using this method for the last 12 months and never had any issues, I would suggest that if small water changes of say 10% are made and salt water is mixed indoors they is no need to heat the mix as the tempreture change is insignificant assuming an ambient of 19 to 21 c."
I always left it overnight with a pump and heater as well... Maybe I'll give the instructions a try and see if their is a big difference.