Zip Bag 12.5 x 5.5 in and 19 x 17 in — Zippered Filter Media Bag in Three Meshes - Seachem

The Seachem Zip Bag is the filter bag with a corrosion-resistant zipper, offered in three meshes: Small 25 mesh (the tightest of the trio), Medium 16 mesh (the all-rounder) and Large 8 mesh. Made of PVC with stitched seams, and resistant to bleach, caustics and acids. Small and Medium measure 32 x 14 cm (12.5 x 5.5 in) and easily hold 1 L of media according to Seachem; the Large measures 48 x 43 cm (19 x 17 in).

Three meshes, three jobs

• Small — 25 mesh: the tightest weave, for fine granular media. This is the documented mesh that drawstring bags can't offer — the case of microparticle phosphate removers like RowaPhos.
• Medium — 16 mesh: the do-everything bag. Seachem's official list: PhosGuard, MatrixCarbon, SeaGel, de*nitrate, Renew, Matrix and zeolite.
• Large — 8 mesh: careful — it's the COARSEST of the three, not a scaled-up Small. Seachem aims it at Matrix and Pond Matrix in bulk volume.

For very fine resins like Purigen, even 25 mesh is too open: Seachem calls for a bag of 180 microns or less — its The Bag, with welded seams.

Available sizes

• Small 12.5 x 5.5 in (32 x 14 cm), 25 mesh — UPC 000116015226
• Medium 12.5 x 5.5 in (32 x 14 cm), 16 mesh — UPC 000116015219
• Large 19 x 17 in (48 x 43 cm), 8 mesh — UPC 000116015059

Why buy from ReefSolution

In business since 1999, with over 118,000 orders processed since 2010. In-store advice in Laval, QC, shipping anywhere in Canada.

Our advice

Seachem's Zip Bags are a fancier bag — much finer, and they'll last much longer. It's a bag that costs more, but the quality is a step above. The meshes are really fine — there's also a coarser large one — but they're still far tougher and will outlast ordinary bags. And they close with a zipper: nothing to tie off, no wrestling with the bag when it's time to change it.

— Stéphane, Aquarium ReefSolution

Frequently asked questions

Which mesh should I pick: 25, 16 or 8?

The Small (25 mesh) holds fine granules, the Medium (16 mesh) covers Seachem's official list from PhosGuard to Matrix, and the Large (8 mesh) is built for big media in bulk.

Is the Large finer than the Small?

No — it's the other way around. The Large is the coarsest of the three (8 mesh versus 25 for the Small). It's a volume bag for Matrix and Pond Matrix, not a big fine bag.

Zip Bag or The Bag?

The Zip Bag is the rugged zippered bag for granular media. The Bag, with its 180-micron mesh and welded seams, is the only one of the two that holds fine resins like Purigen.