You'll be rinsing the sand even longer than the gravel.
The best way to rinse gravel or sand, though, is to put it in a bucket and use the hose. You don't need to use hot water because you don't need to sterilize it. You just want to rinse off any loose particles or dust that could cloud up your tank.
Anyway, pour the substrate into the bucket and fill it with hose water, enough to cover everything. Swish it around and then pour out the water. Repeat until the water runs clear or as clear as you want it to be. With sand, you could be rinsing for a loong time. It took me two hours to rinse 20 lbs. Well, good luck! Post pics of your tank when you've got it all done. :)