Your normal knot is fine, but it sounds like you're not testing the knot after tying. All knots will slip occasionally because you're human but if you test them you'll catch the bad ones before the trout do. There's no reason to lose a fish to a bad knot, you just have to test it. You can't do that in your fingers you need a strong anchor.
With a hook I put it though the finger hole of my forcepts and pull really hard. Or use a zip pull on your vest. I reckon 1 in 4 knots fail the test.
I'd do the same test with a ring once the hook is attached.
Interesting. I've recently been questioning the diameter and knot strength of some of the "high tech" monos. This was prompted by me hooking a big, hard fighting fish on a low breaking strain hook length (coarse fishing!). I've been using the same line as a tippet material whilst trout fishing and it has performed well. I spent a pleasant afternoon measuring line thicknesses with a micrometer and doing some comparative tests using various knots. Broadly speaking the results were:
Many "high strength" monos have larger diameters than stated on the packet - typically between 10% and 15%
Tucked half blood knots worked best (vs palomar and grinner) on fluorocarbon
The palomar worked significantly better than the grinner or tucked half blood on "high strength" copolymer lines. In some cases the line snapped before the knot.
Experience (to some extent now backed up by the above) has shown me that using 2 efficient knot and a ring to join two or three lengths of line is much more reliable than using an inefficient knot like a water knot to do the same job.
Davy knot for me. Its a brilliantly simple, small and strong knot and there is hardly any friction when pulling it tight, so you wont get kinked line. The tucked half blood is a strong knot, but with a fine line and tippet ring, no matter how carefully I pulled it together and no matter how much saliva I put on it, I would always get annoying kinks and thus a weakened leader.
I cannot tie a perfection loop, sometimes they are"perfect" but the next couple of loops just turn into a sliding overhand loop, why?
I am only practicing at home, with braided line using the Orvis Perfection Loop animated guide video
are there better knot learning aids?
A bit late... For nylon I have 100% confidence in the uni/grinner knot.
For fluorocarbon to tippet ring I prefer a tucked blood knot.
If you're getting a pig tail there's something not right with the tying.
I don't mind tying the occasional tippet ring with it but in general I don't use a blood knot, i find it requires to much fiddling and seating to get it 100% right or you will end up with a pig tail...
If you tie two efficient knots to a tippet ring; surely that will be stronger than a less efficient knot used to join a piece of tippet to the leader. That assumes you practice and don’t tie ‘bad’ knots.
i use tippet rings for permit and bonefish. Primarily because I get a stronger connection than if I try to attach a Fluoro tippet to a mono tapered leader with a surgeons knot Or other straightforward knot. I guess I could use a Bimini and a slim beauty (or similar) but the tippet ring arrangement works for me.