Hello Life~Reefer,
Thanks for the post, let me first suggest to you not to open the Chemi-Pure bag, it is very messy. You can use the bag of chemipure (Chemi-Pure) in its bag in the reactor you will need to make sure that the media in the bag is easily spread around in the chamber, the main reason the (they) suggest not to us (use) media with a mess (mesh) bag is because over time the pores in the mess ( Mesh) bag will become clogged with debris.
With this type of reactor it is normally recommended that the media used is not in a mesh bag, the free floating media in the reactor makes better contact with the water ( in the water column) to remove undesirables. I hope this information helps.
Please fee (feel) free to contact us with any further questions you may have.
Best regards
Walter
Marine Depot Customer Services