Quote Originally Posted by STEvil
part of the problem is the inlet and outlet of the bend having a "step" for the water to hit.
You are going to have that little "step" every place that tubing goes onto a barb no matter what you do, and that little bit isn't going to make a measurable difference at all.

Two 45 degree work fine, although I have grown to use a long sweep elbow in that it provides a smooth yet compact 90 degree transition. Even two 45 degree elbows are not smooth and take up more space.