CLI-521BK - why is the ink level hard to see?

[OM2]

CLI-521BK - I always have problems seeing the correct ink level
The ink JUST sticks inside - or at least seems to!

Does everyone have this problem?
Could it be the ink I refill with?

I don't have the same problem with any of the other ink cartridges I refill

Thanks


Omar

 

[PeterBJ]

I think all inks behave that way, even Canon OEM. By nature dye and pigment black inks are very opaque. Holding the cartridge up against a light source makes seeing the ink level easier, but I admit it can be difficult to see with black inks.