The standard flyline backing is 20 pound Dacron. This usually comes in white, orange and chartruese. Pick a color that differs from your fly line. Remember that REAL men never even SAY chartruese let alone know how to spell it.

Now the true secret is to put the fly line on first then the backing as you never know how much to really use. Keep it about 1/8"-3/16" under jamming your reel up. Then remove it and reverse it. But this is too easy.

Now back to what the non-experts do. Use as much backing as called for on your reel box. DUMB!!! Reel makers LIE! Don't you know that yet? Good grief, ROOKIES! Let's use Okuma as an example. Some of their reels call for 100 yards of backing and they REALLY hold only 50 of it. Liars! But they are tricky, too! Another Okuma reel calls for 120 yards of backing and it holds almost 110 yards. Tricky buggers...not even the same percentage. Now Loomis is trickier yet. Their recomendations are right on. I HATE it when they do that as it never happens.

The recomended amount also varies with the weight line you use. You get a lot more backing when you use a 3 wt rather than an 8 wt. Like you really need 125 yards of backing on a 3 weight. Tricky buggers again.

You get more line if you carefully apply the line. The more unnecessary crossovers, the less line you have room for. Now my boss demands we use the nail knot for backing to line and line to leader. Probably so he can sell more line as the salmon takes off with it.

The line manufacturers get even more devious. The line is placed on spools with wings which tangle at every turn. Worse yet, the spools are split so that they open up as soon as you touch them tangling the line for at least 30 minutes. That is the industry standard. Now the Cortland 333 is a baby puke green color which you cannot even stand to look at making it more like an hour to untangle.

I use a line turner with foot pedal (designed by line manufacturers to jump speeds to cause more problems). I place the fly line on the opposite arbor, line them up and lock the end arbors BEFORE I take the twisties off the fly line. This keeps the line from jumping off into tangles. Fly line companies really hate me for this. They also hate me for buying new fly lines only about every 40 years. An old dry line makes a perfectly fine sinking tip line after this many years.

I think it is Cortland again that had a monfiliment-like clear fly line. These are very slick so use a really strong backing to fly line. These buggers get trickier every year! I never get free fly lines...wonder why?

By the way, unless you have an unusually wide arbor reel, don't put on any more backing than about 1/2" to the low side of your reel spool.