Improved clinch for most trout flies, and a Turle for up eye heavy fish (steelhead) flies. The only time I ever had knot issues was when a tech rep gave me a bunch of high end, thin for it's weight rating, leader material. I think it was Diawa or something similar. Lost 5 steelhead to flies stripped on the take, each coming in with a curly cue on the end. Given their rarity, missing a steelhead is a significant issue to me.
Back in camp, I put things together and with pliers gripping flies, the leader wound around a stick, I attempted to pull several assemblies apart. One could watch the tag end of the knots spin around and come unglued. A solution was to put additional turns on the knots like 7 turns instead of 5 on an improved clinch. It's difficult, however, to get that many turns to stack properly. My solution was a visit to the dumpster and a return to my long used Maxima.
Best knot is a Bimini, but that's for huge salt water fish, and not something we would rig for a size 22 midge.
Heat and UV light are both killers of leader material. I assemble mine, buying 200 yd spools, and make every effort possible to keep the material out of the sun and never left in hot locations like a rig on a hot day.
Another thought: Do wet ones knots before putting the final tug on to cinch the wraps. That exercise on dry material can also generate brief but significant heat weakening the material in that local.
Also, if I have an extended fight with a heavy fish, I will cut off and replace the weakest tippet. Excessive stretch in a long duel can weaken the material such that it can not withstand a sudden heavy shock.
Your knots are fine, I'd be inclined to blame some aspect of the material.
Good luck out there,
Last edited by 1minute; 07/21/18.
