You can get elbows for tubing in many sizes and many materials but not in PVC. This was the last detail in a big ElectroScan sanitation system install, it's the brine tank connection. The install is under a set of stairs and a straight barb plus tubing wouldn't clear the stair tread. I couldn't even find the barb for sale in PVC, turns out it is custom machine. I decided to design a part that I could cement to the barb to make an elbow while keeping the same inner diameter all the way through. After a number of turning and milling steps I cemented it together and it worked perfectly.