I tried the pop out the hole, fill up the tank, plug the hole and hope not much leaks out. It works, but what a mess!! This is what I do. When the ink looks low, I turn the cartridge upside down and slooooooly inject 3-4 ml of ink into the small round sponge area where the ink leaves the tank. You can see the sponge filling up. I DON'T overfill !!! I leave the tank upside down for about 5 minutes so the ink can settle in the sponge. I then turn it over and dab the small round spongy area on a wad of rolled up toilet paper a couple of times. There is enough ink in the tanks to do a lot of printing. I print a lot for my business (mostly pictures of houses on 32 pound paper) and this method will last a couple of weeks printing 60-70 5x7 color pictures. Also quite a few reports. For a normal household, should last a month or two. No mess!! No fuss!!
Bob
Bob