Refill ink question

I bought a Nukote Ink Jet Cartridge Refill Kit RF197 for my 940C HP printer with C6578 Color Ink Cartridge. I havent done it yet, but the instructions says to punch out the 3 small holes on top of cartridge, but it says nothing about plugging the holes back up after I refill the ink. On my NuKote Cartridge Refill kit for my black ink cartridge, it tells me to make sure I cover the hole back up with the tape they provided. So why cover hole up on black ink cartridge but not on the color ink cartridge ? It doesnt make sense to me. I figured the ink would dry out if you dont plug the holes back up. So could someone please shed some light on this for me.

On the black the hole is at the bottom of the cartridge so it’s necessary to cover it.

On the colours it doesn’t matter as there’s a foam cover that you push the needle through which effectively seals it.

Sometimes the holes you are putting the ink through are the air intake holes. If you cover them, what happens is a vacuum develops inside the cartridge and eventually no ink will come out because of the pressure difference. Other times, you are putting other holes in it and these might leak ink and so they should be covered. Normally even with new cartridges there is at least one hole for air intake.

K thanks TimC and lui_gough. You guys cleared that up for me. :clap: