Hat I think you are misinterpreting or misreading what I mentioned in my posts:
Hat : "Covering the air maze will limit the amount of ink going into the sponge area that is all, .....
Thats why I suggested only filling the reservoir to 75% when not covering the air maze,"
Precisely, that is what said at post #7 that the vent or air inlet hole should NOT be covered so soon. Before Tudor edited the post, it depicts the clay over the vent/air inlet hole before starting refill. The reason why we cover the vent hole/air inlet hole AFTER the sponge had absorbed the refilled ink from ink chamber, is because by now the sponge would saturated/absorbed with about 3/4 of ink. And you want to stop the sponge from absorbing ink further to avoid oversaturating/overfill the sponge compartment by covering the vent/air inlet hole. At this point, you are stopping the air and ink exchange process for which the sponge to absorb further ink.
Hat: "If the air maze on the otherhand is covered the sponge stops absorbing ink when the pressure builds up above the sponge,
because the air above the sponge is now trapped and has nowhere to escape too."
Now let me ask you, where does air from the sponge chamber, goes to during air and ink exchange from the ink chamber as the sponge absorb the ink? The air from sponge chamber goes into the Ink Chamber via the grooves holes at the bottom of the cartridges. That's the ink chamber where you had a needle inserting into the refill hole to inject ink.
During the refilling process where the refill hole is open, with the storage clip sealing the exit port, "[Hat] If the air maze on the otherhand is covered the sponge stops absorbing ink when the pressure builds up above the sponge". Now ask yourself what kind of pressure are you building up or where or who or what is giving the pressure, or how does it build pressure, on it's own? If it's the refiller giving the pressure by keep refilling the ink chamber with ink, then shouldn't the refiller stop what ever he is doing. Ink that refiller
keep injecting non stopand where
"the air maze is covered and sponge stops absorbing", the ink at the ink chamber will backflow out to the top where the refill opening hole is. Why, because there is no other hole (giving that the air maze is covered) for the influx of ink to exit itself.
Now pls note that at the point of writing at post #7 and #9, the first post didn't include the picture of the bottle flushing and drying a cartridge. So I am not referring whether it's a purged cartridged or not. It's only subsequently Tudor update the first post to cover the flushing/drying of cartridge. But whether or not it's a used cartridge where the sponge is not too dry or a purged cartridge where sponge that is very dry, it's still the same. You must allow the air and ink exchange process to take place for the sponge to absorb the ink. During refilling (obviously the vent or air inlet hole is NOT cover up), when your sponge is absorbed partially with ink whether it's 75%, 80%, 85% etc whatever, THEREAFTER you cover up the vent hole/air inlet hole at that point when you want to stop the sponge chamber from further getting overly saturated/overfilled.
But what mrelmo had asked regarding first covering and THEN fill up and THEN remove the thumb and .... (Refer to his post #13 for details). This can be done as well. As at some point, you remove/release the finger/thumb/clay etc for the sponge to absorb to with ink as air from sponge compartment goes into the ink chamber.
