Biomax Cartridge Fluval – U4 Filter

Biomax Cartridge Fluval – U4 Filter

Compatibility

What it is. BIOMAX biological filter media for Fluval’s U-series internal filters. Fluval’s own U-series parts list shows this as a single shared item (A495, sold in a 170 g bag) used across the U2, U3 and U4 alike; it’s the same ceramic media in every size, not a separate mould per model, with the quantity loaded into the central media cartridge varying by which filter it’s going into.

Where it sits. Loaded into the U-series’ central media cartridge, rinsed and placed there after the mechanical foam stage: the biological stage of the filter’s overall three-stage filtration.

Setup & Use

Before first use. Empty the bag into the central media cartridge and rinse under a running tap before fitting: new BIOMAX carries manufacturing dust that clouds the tank if it isn’t rinsed first.

Ongoing care, per Fluval’s own maintenance schedule. Rinse it every week in water taken from the aquarium during a partial water change (never tap water, which kills the beneficial bacteria the media carries) and follow with a dose of Fluval Cycle to replenish what’s lost. Only replace half the BIOMAX at a time, every 6 months, again dosing the fresh half with Fluval Cycle; Fluval is explicit that you should never replace all of a filter’s media at once, to avoid wiping out the bacteria colony in one go.

Freshness & Storage

Every batch we dispatch carries a minimum of 6 months’ remaining shelf life. Store this product in a cool, dry place away from direct sunlight, with the cap or inner foil closed tightly after each use.

Filter media and substrates carry no manufacturing or expiry date: their working life begins on first contact with water, not on the shelf.

Returns & Replacement

Returns are accepted within 7 days of delivery, provided the item is unused and in its original packaging. Manufacturer-sealed items cannot be returned once the seal is broken, and sale-priced items are not refundable.

If your item arrives defective or damaged, message us on WhatsApp with your order number, or email us if you would rather, and we will replace it. Approved replacements are delivered within 3 to 5 business days. Transit damage is covered by insurance on every shipment. If tracking shows delivered but nothing reached you, tell us within 48 hours, which is the reporting window Indian couriers allow. Damage caused during installation or use is not covered; replacement spares for such cases are chargeable.

Full terms are on our Cancellation & Returns page.