If it was going to do any damage, I'd bet it would be immediately apparent - so I think if all looks well then no harm, no cause worry.
I wouldn't make a habit out if it though.
FWIW, from setup, to pouring the water, to mixing, through cleanup I can do a whole 5 gallon water change in about 10 minutes or less without hurrying.
Not that anyone needs to necessarily go faster, but it doesn't have to take more than 5 minutes or so for most salts to completely dissolve. If it takes you any longer (and you see that as a problem), get more creative with how you set up your mixing pump.
Even using a manual mixing paddle like these followed by air stones doesn't take much longer. (Don't cheap out on the air pump if this is your method. Along with the paddle, I have used one outlet off a Fusion 7 air pump - which is not expensive - to mix two 10 gallon vats with good results.)
SOCAL619: Always, always, always pour the dry into the wet. This goes for food baking, cement mixing and especially mixing artificial seawater. There is much more chance for precipitation to happen if you instead wet over the dry, which will cause your water change water to be reduced in calcium and alkalinity.
Hope this helps!
-Matt
