knot question

[hooked]

I was reloading line after cleaning a reel and decided to test the knot holding the braid to the mono backing. It failed way too easy. I've got 50# braid connected to 20# big game by a uni-uni knot.

I cut and retied but I still could cause the knot to fail before the 20# line would snap (but with a lot more effort than with the first try)

Nothing I caught last year took out more than the 150 yards of braid but I'm hoping to change that this year.

Does anyone have a suggestion for a better knot or method?

I was thinking a loop to loop might be better but I'm not sure it would lay down on the spool properly.

Thanks