DON"T TOUCH THAT DIAL!
You don't want to test it. Trust me. IF, you hit print...after you get the message of M-Tank low,....(it's really low).
You stand the chance of running the pump dry. If you run the pump dry. You have to sit on the side (in an uncomfortable spot) for like 30 min. Pulling on a syringe to draw the ink through the lines of the main tank...back up into the pump. Time consuming...and inky.
Don't be fooled by the 200-250ml in the bottom of the tank. That is there to help keep the tank and pump primed. There is a tube that runs down near the bottom of the tank (just above the bottom) so that it does not suck up any sediment. That tube, must be full covered well, with the remaining amount of ink left in the tank (what most all think is plenty to do the next job of 2-4 screens.....is not.