I also use frog hair 4x and 5x. For years never had any problems, but lost three big fish last season, which happens but all seemed to snap way too easy, and after the effort finding and hooking them I was gutted to say the least. I did change tippet spool. So I'm either really unlucky with tippet or knots slipping or doing something wrong 😳
Thanks again I may try grinner knot, if anything just for renewed confidence
Geoff