If you are using two different kinds of line for your leader and tippet that will weaken the connection.  I've done some reading on the subject and it apears from tests that the good old blood knot is the strongest connection here.  I'm lazy, though, and almost always use a double surgeons knot.

JT-

When you say that using two different types of line weakens the connection, due you mean, for instance, mono and fluoro, or do you just mean two different brands of mono?

I have been using Rio mono leaders and tippet material in 5x. So far I have been happy with the performance of the Rio brand. I haven't tried flourocarbon since I can't stomach $12 for spool of tippet material.

I use a triple surgeon's knot to attach the tippet to the leader. I too have had some breakage at this connection, but not all that often. I make sure I put a little spit on the knot before pulling it together to make it set nice and tight. I also leave a little extra on the tag ends to allow stretching/tightening of the knot.

hey chuck just remember even though you have glue you have to bring those fish in quick before they get off, CARSON, hahaha, good times though, gonna be going again on thursday next week, keep them flies went on the truckie and bring me back some pics

I just use the ol blood knot for leader to tippet connection, I too always use rio mono leaders and rio mono tippet material, I never have had break off problems with this setup, I have thought about using a dab of super glue, Good idea chuck.  The flourocarbon in my opinion isn't worth the price. But awhile back the store in winters had a bunch of mismarked flourocarbon tippet spools, HAHA They were only like 3 or 4 bucks, So I picked a few up. I also never ever use the same tippet for more then one trip, Every single fishing trip gets a fresh tippet, Many times I also will tie on new tippet a few times thourghout the day. Also make sure you are wetting your knots before you sinch em down, use saliva or water. And if the blood knot isnt perfect I start over with another one.

I use Rio mono leaders, and rio fluorcarbon tippet. The fluorocarbon tippet will really help to catch more fish. You can usually use one size up 4x versus 5x and land more fish. If you haven't used Rio super fluoro then you should try it. In most cases you really don't use a lot of tippet per trip. The few extra dollars is definitely going to catch you more fish. I also think it is stronger than mono.

Captain did you see any improvement with the Floruocarbon. Stronger? more Bites?

I fished with Otter once.  He was hammering fish, and I couldn't buy a strike.  We were using the same setup, the only difference was the tippet.  He was using fluorocarbon, and I was using monofilament.  I have since switched to fluorocarbon.  I use Cabela's Prestige Plus tippet material.  It is Gamma Processed, the same process that Frog Hair uses on their fluorocarbon to make the line more flexible and stretchy.  It's $14.99 for a 50 yd spool.

gotta love those putah mach trucks sometimes they just get outta control and you cant do nothing about it,

well dont know if anyone would like to know, but jt was laughin at me cuz i was using a 9 wt rod with 5 wt line, yes a telephone pole with very small line, but it was working for me, but i have now upgraded very well pickin it up tonight, and first thing thursday with be tearing into those putah pigs

this is what i got

St. Croix 9'Imperial fly rod 5WT 4 peice
Rocky Mountain Orvis
line backin everything for 140

and on top of that got my 50 flies i ordered from blueflycafe.com for 38 bucks and these are actually very very good flies, well built, look really good, cant wait to try them

well see you all on the creek

hey fly girl still waiting to try those famous cookies, you are more than welcome to join me and lilwhippersnapper on thursday, just pm me and ill let you know where we will be

Wet the knot when tying, I just pass mine through my mouth before I cinch it down and get some spit on there, otherwise the friction significantly heats and weakens the line as you tighten it down. Something that hasn't been mentioned is how you're playing the fish, it may be that you need to set the drag a bit looser, let the fish run a little more or try steering it to the side away from trouble if possible.

The weak point in the chain is the knot at the fly and at the tippet, if you're breaking at either of those places it isn't necessarily a bad knot (though that's the first thing to look at), and if it's an explosive run by a big fish there isn't necessarily anything you can do about it. But it does help a lot to stop after every break-off and try to figure out if there was something you could have done differently to avoid it. Could be the knot, or how you play the fish, or maybe you've been using up some old stock of tippet material that's been out in the sun too much, or the tippet got damaged during casting or a snag or from a split shot or other gear attached to it, etc. I was getting an unusual number of breakoffs that I couldn't explain, I figured it might be some old-stock of tippet so I tossed it and got some new stuff and the problem disappeared, though I may have become a little more diligent about my knots at the same time.

Just for kicks you might want to start checking your rig periodically by tugging at all the knots and connections and see how they're holding up, maybe even every 5 minutes or so just until you get some confidence in your knots. Definitely check them after you tie them on and before the first cast.

When it comes to drag, I keep mine a lot tighter than I used to.  You'd be surprised how tight you can have your drag and still have a beast pull line off your reel.  When the fish give me a chance, I horse them.  When they want to run, I let them.  You don't want your drag too loose.  Then, you might end up over-playing the fish. 

Most of my break-offs come when fish get line around rocks, submerged bushes, and reel handles or tippet spools.  I really hate those last two, and there's only one person to blame for those. 

oh yeah... What pound test is that.

Isn't that a little heavy with a size 20 nymph

I don't use 4X for flies #20 and smaller.  Some do but not me.  In fact, I use 6X for the tiny flies.  I use 5X to the first fly (if it's bigger than #20) and 6X to the smaller fly (if it's smaller than #20).