why do you age the water?
Several reasons really. It allows time for the suspended salt particles to completely dissolve, oxygenates the water, allows it to chemically stabilize, brings the PH in line and allows time to heat to temp. After 24hrs and after the proper temp is reached you should check the salinity to make sure it's still where you want it.
I would also recommed a MINIMUM of 24 hours. 36 hours or longer is best IMO.