With Steelhead I normally bring in 70% of the fish. I normally do not have a knot breakage issue. If I do it is normally something where I am fishing light tippet 6x for trout and I hook into a larger trout then I expected and do not play the fish properly.
Where are you breaking your tippet at leader to leader or at the fly? If it is at the fly I would try someone like Davy's knot. If it is leader to leader I would look at the knots you are using. For myself I will change out my tippet a couple times a day depending on how many fish I catch. You could also be breaking off from nicks on leader/tippet.
It is important to keep track of of where your breaks come from and then look for solutions at those points. Good Luck