I was excited to find some Montblanc Permanent ink, so I got a bottle of blue and some cartridges of black. The blue is amazing, by the way, I'm using it with a Lamy Al-Star, no issues there, beautiful color, normal flow. But for the (black) cartridge, I'm chose to use them on my Italix Parson's Essential, with a medium nib. I obviously washed the pen before changing the ink. But after I'm not using my pen for one or a few days, the flows stops. I need to really shake the pen, or use filter paper to convince the ink to start flowing again. Sometimes I just rage quit and get the nearest pen to write with, when I'm pressed by time. It's frustrating to spend preparing a couple of minutes every time I need to write something. Is this because the black ink is thicker? Is this issue that I'm having a normal behavior? What can I do to have a quicker flow down the nib? It never happened before with this pen, but I was only using Pelikan Royal Blue with it until now.