Aquario Neo Bag Minus

A mesh filter bag that adsorbs negative-ion (anion) components — nitrite, nitrate and phosphate.

To adsorb is to make something stick to a surface: the media pulls these compounds out of the water and holds onto them, rather than adding anything in. Nitrite and nitrate are waste chemicals produced as helpful bacteria break down livestock waste; phosphate comes mostly from uneaten food breaking down. All three build up in any stocked tank.

In Aquario's own words, Neo Bag Minus adsorbs “nitrites, nitrates, and phosphates of negative ion (anion)”, which they describe as “toxic to organisms”, and also “adsorbs harmful negative ion components other than the above components”. Alongside the adsorbent it carries organic carbon beads, which Aquario says feed the bacteria that break down nitrogen compounds and pollutants biologically as well as chemically.

Despite the name, the “Minus” refers to the charge of the ions removed, not to a pH direction. Aquario make no pH or hardness claim for this bag in any source we could find — it is a nutrient and pollutant media, not a water-chemistry adjuster (pH being the acidity scale, hardness the water's dissolved mineral content). If you have seen it described as softening water or lowering pH, that looks like a mix-up with Neo Bag Plus, which is the bag that carries those claims.

What that does in a tank: it pulls nitrate and phosphate out of the water column — the open water itself — which is the pairing that usually drives algae. The effect depends on how much media you run against your bioload (how much waste your livestock actually produce) and feeding, and it slows as the adsorbent loads up.

• Adsorbs anions — nitrite, nitrate and phosphate; no pH or hardness claim from Aquario
• Organic carbon beads support bacteria removing nitrogen compounds and pollutants
• Aquario dosing: 1 bag per 60 L, or an extra bag if you want a quicker effect. 8 bags per pack, each 12 × 8 cm
• Regenerable — Aquario: shake the bag in 300 ml of 10% salt-water solution for about 10 minutes, soak for a day, then rinse thoroughly with clean water. Performance falls off over repeated cycles
• [NEEDS VERIFICATION] — Aquario's “the energy ball slowly disappears after a month or two” line appears on both Minus and Plus, so it may be copy-paste; treat the service life as unconfirmed for this bag