I use HT Polar vinyl coated tip up line. It has to be vinyl coated. This makes it freezeproof so you can use it on spools below the water and above the water. It has incredible strength and shock resistance. I use the 15 and 25 pound test. I tie the end of the line to a barrel swivel, and then add on a 12 pound fluorocarbonl leader 10 feet long. For pike, add a foot long section of 30 pound fireline to the end of the fluorocarbon. The fireline cannot be cut by a pike's tooth. It is very tough, and way easier to handle than wire leaders.