PGI 520 accepts ink only less than half.

[nche11]

Printer: Canon MP550


Here, I am facing with two problems: firstly, why would a cartridge accept only 25% ink and secondly, is there a way to clean up the presumably-clogged cartridge, as mentioned above, so it works like new one (well, almost)?

It is an issue with the German refill method and it was discussed in this forum before. I had this problem too and I do not refill with the German method any more. The solution provided by experts was to empty the sponge as much as possible before refilling. The refill process is basically filling ink to the reservoir and at the same time air is driven out. The outgoing air would take some ink along with it on the way out through any openings that exist, including the large ink outlet hole, the vent and the small hole you drilled to fill the needle through. If there is much ink remaining in the sponge the outgoing air will just force the ink going in every direction possible for the ink to go. It will find the ink outlet, the vent and the drilled hole and here you go the spill of the ink.