I have a 10' run of 1/2" pex I want to run under a slab that will be poured. Everything I have read says that you must use a non-metallic elbow (such as PVC) to bring the PEx up through the slab. I am running this line for an island sink supply. I would feel more comfortable if I not only ran it through pvc elbows, but through pvc for the length of the run as well. This just in case it failed it would be so much easier to replace. Is there a reason I should not do this?

Use the black poly pipe that comes in a roll. Make sweeping curves so as to not kink it and tape the pex and the poly at the top of the poly about 6 inches above the slab.