can i mix arborio and carnaroli
Both arborio and carnaroli are used to make risotto. 

If you are making risotto the proper way with adding in your stock over time you will be able to control how much liquid overall goes into the rice and therefore be able to adjust your overall liquid amount as time progresses. Carnaroli has a higher starch content than arborio, but if you mix them together and make risotto I am sure it will turn out just fine and no body will notice. Yes they are different grains, but not enough difference to change things.

About Carnaroli

Older discussion re: Carnaroli vs arborio