The Bag — 180 Micron Welded Seam Filter Bag | Seachem

The Seachem The Bag is an innovative, welded-seam filter bag with a superfine 180-micron mesh, designed to hold all types of filter media, including the finest resins like Purigen and CupriSorb. Unlike bags with sewn seams that degrade and leak resins, The Bag uses durable welded seams that resist bleach, caustics, and acids—ideal for filter media regeneration. It has a convenient 13 x 25.5 cm (5" x 9.5") size and a resealable plastic tie closure.

Main advantages

• Welded seams — no degradation from bleach, caustics or acids, unlike stitched seams
• Superfine 180-micron mesh — retains even the finest resins without leakage
• Bleach resistant — perfect for regenerating Purigen and other media
• Resealable plastic fastener closure — secure and easy to use
• Compatible with all Seachem filter media

Use in reef and marine aquariums

The Bag is the benchmark filter bag for fine resins that leak from ordinary sewn-seam bags. Its 180-micron mesh is fine enough to retain Purigen, CupriSorb, HyperSorb, and all synthetic resins while still allowing adequate water flow. Its resistance to bleach and acids makes it indispensable for Purigen regeneration (soaking in a 1:1 bleach:water solution) without damaging the bag. The Bag can safely hold approximately 500 ml of media.

Technical specifications

• Dimensions: 13 x 25.5 cm (5" x 9.5")
• Mesh size: superfine 180 microns
• Closure: resealable plastic fastener
• Material: polyethylene
• Seams: welded (not sewn)
• Capacity: approximately 500 ml of media
• Resistant to: bleach, caustics, acids

Media compatibility

The Bag is compatible with all Seachem filter media including: Purigen, CupriSorb, HyperSorb, PhosNet, PhosBond, PhosGuard, Aquavitro Phosfiltrum, MatrixCarbon, SeaGel, Renew, Zeolite, Matrix, de*nitrate and all other media in the range.

Comparison with Seachem Zip Bags

• The Bag (5" x 9.5"): 180-micron superfine mesh, welded seams, plastic closure — ideal for thin resins and all media
• Zip Bag Small (12.5" x 5.5"): 25 Mesh, stitched seams, zipper closure — ideal for PhosNet, PhosBond, MatrixCarbon
• Zip Bag Medium (12.5" x 5.5"): 16 Mesh, stitched seams, zipper closure — ideal for PhosGuard, MatrixCarbon, denitrate
• Zip Bag Large (19" x 17"): 8 Mesh, stitched seams, zipper closure — ideal for Matrix and Pond Matrix

Manufacturer's precautions

• Do not overfill or overpack the bag — the media should rest loosely enough to allow water to circulate
• Excessive filling can force welded seams to separate
• Maximum safe capacity: approximately 500 ml of media

Why choose The Bag from ReefSolution?

The Bag is the essential accessory for using Seachem Purigen, Seachem CupriSorb, and all fine filter media. Its bleach resistance makes it reusable for years through multiple regeneration cycles. Combine it with Seachem Purigen for organic filtration, Seachem PhosGuard for phosphates, or Seachem MatrixCarbon for activated carbon.

Frequently Asked Questions

Why use The Bag rather than a regular filter bag?

Filter bags with sewn seams degrade in bleach and can allow fine resins to leak. The Bag uses bleach-resistant welded seams and a 180-micron mesh that retains even the finest resins, such as Purigen. Essential for regeneration.

How many Purigen tablets can The Bag hold?

Add approximately 500 ml of media safely. Do not overfill to allow water to circulate around the media and avoid stressing the seams.

Is The Bag reusable after regenerating the Purigen with bleach?

Yes. The Bag is specifically designed to resist bleach, caustics, and acids. It accompanies the Purigen through multiple regeneration cycles without degradation of the welded seams.