Two other ideas - I use quicksets, was getting no del, appeared secondary to bent cannula. Tried everything, no luck, until finally I quit using skin tac before insertion. Problem solved, I now insert (alcohol prep only) and then soak outside of quickset tape with skin tac, stays in place 3 or more days!
Also, do you do site change when you are able to immediately do a "large" bolus of insulin? I also find if I do a site change with what the pump wants to prime the cannula and then just allow my basals to run, I have problems. So I always plan a site change when I can bolus. Again, problem solved (especially w/blood in the cannula).