It's always best to weigh your salt, but if the recipe you are using gives volume measurements of a particular common popular brand and type of salt, then you can work out the equivalent weight. What exactly does your brine recipe call for?
Regular table salt, such as Morton's table salt or pickling and canning salt, weighs about 10 ounces per cup. Morton's Kosher Salt weighs about 7.7 ounces per cup. Diamond Crystal Kosher Salt weighs about 5 ounces per cup. So if your recipe calls for 2 cups of Morton's plain pickling and canning salt, you would need 20 ounces.
Also, see this page.
http://www.dadcooksdinner.com/2012/02/s ... eight.htmlYou should avoid using salt with iodine and anti-caking additives when brining, pickling, canning, making sausage, cure blends, etc.