I was not very far into my pursuit of smallies this summer when I started to get all sorts of line twist when I was throwing heavy poppers or bigger terrestrials. There were times when it was so bad that I could see the fly spin like a propeller on the end of the line after plopping into the water. Not good. I'm sure that did not look very natural! It also did not take many casts before the tippet became just a tangled mess which took a few minutes to hang and smooth back out.
What to do? Drawing on my experience as a spin guy, I knew that swivels were handy when using spinners. The swivel isolates the twist injected by the twirl of the blades. So, the next time I was at Gander Mountain, I looked carefully through their selection of swivels and was delighted to find these two models.
I was concerned that, even though they are both small, that they would drag my fly underwater. Turns out they both float pretty well as long as the water is not real choppy. If it is, you can put on a very small indicator on the rod side of the swivel and solve that problem. With the normal larger poppers (size 4 - 6) and terrestrials I use, I never had to do that.
Once I had a swivel in line, my line twist miseries totally disappeared.