I have been cleaning heads when I find that even though the cart is showing ink, it is empty or, the cart ran out of ink without showing empty. What is the r3000 supposed to do when it is time to refill? Mine is not doing this. Right now, I have purchased a complete set of carts and did multiple cleanings, and print nozzle checks except for VM are ok. I used the individual kit to force cleaning fluid through this port and it went easily. I then put all the ink carts back in and noticed that the vm cart was actually empty but show ing about 1/8 inch on the printer?