Need help.....tippet problem

Had a problem on thur with Seaguar 6# tippet. I just purchased it at Elk Creek bait and it knotted well and worked fine hooking fish. For whatever reason broke off twice bringing in fish. It was a clean break, not at the knot but close to where the fishes mouth would have been. I use about 21" of tippet and changed the whole thing after the first break. Then the 2nd happened in the same location, just above hook and below the weight. I am very careful not to "score" the line when adding weight. Played the fish well didn't try to horse them in. Went back to trusty 8# and had no other problems bringing in fish. Could it have been coincidence or what I don't know. Thought it may have been fishes teeth, but what are the chances of 2 fish in a row but wanted to ask opinions. I know guys use 4#. Thanks for any input.

Rio

I don't even use tippett. Just use 2 feet of 6 pound fluro, normal line, sometimes 8#. Sometimes i just put the fluro on a swivel at the end of my fly line with a 2 foot 10 pound shock leader.

Some manufacturers put dates on their spools; old line and even new line exposed to sunlight while in storage can become weak

I had the same problem with Seagar Gran max,have gone to Pline flora and now am buying the 250 yd spools.For the money it can't be beat,the way I go thru it in a season it is very cost affective.

Thanks guys for the help. Never really had any problem with the seaguar 8# but tried 6# beacuse of conditions being so clear. Oh well, think I got a bad spool according to most. When I come back up may have to see if Elk Creek bait can trade me out or just have to make a trip to Poor Richards sounds like.