G4 Ti4400 @ 75C?!?!?

[Kali157]

First off, I have a water cooling setup. I water cool my CPU and GPU (graphics card). I also have 2 radiators so I can cool the water coming from the CPU before it goes to the GPU. Now I am getting my temp reading from the back of the GPU and it is reading 75C. Is that even remotely normal???!?!?!?!what am i doing wrong with my water cooling? I use water and Redline water-wetter. I have a little bit of air traped in my radiator... Is the air causing that much of a problem? Any help would be great.. thank you in advance.