Yes, you can use them together. You might need to pry up the battery contact just a TINY bit. It is "floating" in there and sometimes needs to be pulled up just a bit.
That being said, a lot of people are less than
thrilled with the
tank atty. You might want to try the new echo-e cartomizers on your t-rex. They are MUCH better in my opinion and others seem to agree. Larger volume of liquid (2.4ml), better taste, better wicking, and no flooding.