Fluval AquaClear 20 Power Filter, 5-20 US Gal / 18-76 L

Features

• Multi-stage filtration.
• Easy installation and quick maintenance.
• Unique waterfall design.
• Easy flow control.
• Comes equipped with necessary media.

Compatibility

What it is. The Fluval AquaClear 20 is the smallest unit in Fluval’s AquaClear hang-on-back power filter line, built for aquariums of 5–20 US Gal / 18–76 L — the exact range on Fluval’s own product listing for this model.

Where this sits in the Fluval range. It’s the entry point of a four-size lineup (AquaClear 20/30/50/70, plus the larger AquaClear 110 above it), all sharing the same waterfall-return design and the same three-stage media order — case size, media volume and flow-control range are what change between sizes.

Rim and water-level fit. Fluval’s own instruction manual for this line caps the aquarium glass/rim thickness it will clip onto at 0.9″ / 2.4 cm, and calls for a water level no more than 5/8″ / 16 mm below the filter’s outlet for the AC20 — worth checking both before ordering if the tank has an unusually thick rim or a low water line.

Setup & Use

How water moves through it. Per Fluval’s manual: intake water is drawn in at the bottom of the filter case and travels upward through three media stages in order — Bio-Foam (mechanical), Carbon (chemical), then BIOMAX (biological) — before spilling back into the tank over the filter’s waterfall lip, which also aerates the water on the way down.

Flow control. A flow-control lever sits on the intake "U" tube; at its minimum setting, up to 50% of the water is deliberately recirculated back through the media for slower, more thorough filtration rather than being pushed straight through — useful for bettas, shrimp and other flow-sensitive stock.

Priming. Fill the filter case with water before plugging in, set the flow control to minimum for the first start, and allow 30–45 seconds for the filter to prime before adjusting flow to the level wanted.

Upkeep. Fluval recommends a general clean of the case, impeller cover and impeller every month (rinse only — no soap or detergent), and a full motor strip-down every three months. BIOMAX is rinsed, not replaced, at each monthly clean, to keep the bacteria colony it carries intact; Carbon is a consumable and needs periodic replacement once it’s exhausted.

One box difference at this size. Every AC-series filter above the 20 also ships with an intake extension tube for deeper tanks; Fluval’s manual notes that part specifically isn’t included with the AC20 — not a fault, just this size’s standard kit.

Backed by Fluval’s 3-year manufacturer warranty on defective parts and workmanship, extendable to 5 years total free with online registration within 30 days of purchase at FluvalAquatics.com/warranty. The impeller is the filter’s one continuously-running moving part and, like any wear item, sits outside that warranty.

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.