ALSO.. i am supposed to tie in my 0v from rectified circuit to ground on Arduino yes?
Yes! Voltage needs a reference, or you need a difference.
Your multimeter (if you have one) has two leads and it measures the voltage difference between the two leads.
You also need both connections with your "Arduino meter". In many cases the Arduino is already connected to whatever you're measuring. In other cases you have to be careful because the Arduino may be "accidently grounded" through the power supply or the USB port, etc.
And, if the ground gets connected to the wrong place you can fry something.
If you leave one lead of your (real) meter disconnected, you'll read nothing, or in the AC mode you may pick-up some electromagnetic noise. (Your meter won't float-up like the Arduino.)
Or if you have two identical batteries with a common negative ground, you'll read 0V between the two positive terminals because there is no voltage difference. And, if you connect a load (an LED or a meter, etc.) between those two positive leads, no current will flow and nothing will happen. (That works with a meter because there is no "ground" lead on the meter, just a + and - lead... Don't try that with the Arduino because the Arduino ground may be connected and you might short something out.)
Or, if you try that with a 6V and a 9V battery, you'll read 3V. If you connect the black/minus meter lead to 9V, that is your reference and the meter will read -3V.