From The Aquarium Wiki
What is a Media Bag?
A Media Bag is usually a nylon or polyester resealable bag that you fill with material for placing into a filter or even dropping directly into the tank. The media is usually anything designed to alter the chemical properties of the water.
Typical examples of media
- Ammonia removing resin - Zeolite, Ammo chip resin
- Phosphate/Silicate removing resin - Ultiphos Fe or Rowaphos
- Purigen by Seachem
- Nitrate removing resin
- Active Carbon pellets.
- Calcium Carbonate (shells)
- See resins for details.
Finding these bags is not that easy. Few pets shops sell them so aquarists have had to come up with their own solutions. Here are some examples:
- Nylon ankle socks.
- As long as they are made from nylon and the holes in the material are not too large then they can be useful. However the hole pitch may be too small and due to the multi-layer aspect of this material it can clog easily.
- Voile curtains.
- This is fine mesh nylon curtains designed to prevent insects getting past. They are usually very cheap, widely available from DIY shops and even the smallest curtain is large enough for use as a Media Bag. Cut the material into a circle, put the media in the centre and get a food bag retaining clip to secure the ends. The hole size is not too small (about 300microns) and even fine 0.5mm grain pellets like Purigen is held securely.
- Commerical bags
- 'The Bag' by Seachem. (Seachem)
- Prime nylon media bag by Hydor. (Hydor)
- Rowa Media Bags. (Rowausa)
- Universal Filter Media Bags by Hagen. (Hagen)
- Eheim Media Bags. (Eheim)
- Other commerical bags - Filter Media bags, Nanobags, etc. (Marine Depot)
- Aquarium Micron Pull String Bags - Media Filter Bags. (ocreef.com)