I have used the packets in my marine tanks for ammonia/nitrire.......They worked well.......I don't know anything about the loose stuff you have in the picture.

petsmarts have the mesh bags, but purigen is some good stuff. gets your water clear in no time. Work wonders on removing tanis when you have driftwood.

i don't know for sure, i got my mesh bags from a saltwater shop, i just threw that out there because i know everyone has a petsmart close. But i also use stocken caps, that i put on my head to cover my braids lol. brand new of course. Check with your local saltwater stores, im pretty sure they have somethinge fine to hold the purigen.