I've used Trilene XT for years for spring and fall chinook with good results. It has good knot strength and high abrasion resistance. I trust it.

On a trip two seasons ago to a local river where I fish for fall chinook, I respooled with fresh XT that I had purchased the day before, like yourself. I soon hooked a nice bright fish which proceeded to head downstream at a pretty good clip and POP!, my line snaps. I figured there must have been a nick in my line that I'd missed. It happens. I retie, bait up, and go back to fishing. About a half hour later, another hook up with the same results. So now I'm pissed. I retie and test the knot, POP! I had what was left of the fresh spool in my vest and I test it. POP! It's rated as 17 lb. test and it breaks at what feels like 10 lbs. I had purchased a spool of weak line, perhaps like yourself.

I'd take back the spool that you recently purchased and get my money back. Then I'd go to another store and purchase a fresh spool. Respool and test it before you fish it. My .02.

Ron