AquaClear 20 Hang-On-Back Filter — Multi-Stage HOB 5-20 Gal 18-76 L - Fluval

The AquaClear 20 by Fluval is a hang-on-back (HOB) power filter built for aquariums from 5 to 20 US gallons (18-76 L), in both freshwater and saltwater setups. Its multi-stage system delivers complete mechanical, chemical and biological filtration for clean, stable water.

3-Stage Filtration

Water passes through three filter media included with the unit:

• AquaClear Foam - mechanical filtration that traps debris and suspended particles.
• Activated Carbon - chemical filtration that removes odors, discoloration and dissolved impurities.
• BioMax - porous ceramic media that hosts beneficial nitrifying bacteria.

Waterfall Design and Flow Control

The waterfall return gently breaks the surface tension and promotes oxygenation while operating at a low noise level. A patented flow control lets you adjust output to suit your tank, and the media basket keeps water from by-passing the media to maximize efficiency. According to Fluval, the filtration volume is up to seven times larger than comparable filters, extending media contact time and preserving beneficial bacteria colonies.

Use in Marine Aquariums

Fluval rates the AquaClear 20 for both freshwater and saltwater. In a reef setup, this compact HOB filter is often used as a supplemental filter, a quarantine-tank filter, or a housing for targeted chemical media. The open basket accepts a range of AquaClear filter media.

Compatible Filter Media

The AquaClear line includes media designed specifically for this filter, such as Zeo-Carb and Ammonia Remover, alongside replacement foam, activated carbon and BioMax.

Why Buy AquaClear at ReefSolution

ReefSolution is a marine aquarium specialty store based in Laval, Quebec, shipping equipment across Canada. For routine upkeep, keep the size-20 replacement media on hand:

• AquaClear 20 Foam Insert - replacement mechanical media, rinse in aquarium water.
• AquaClear 20 Activated Carbon - chemical media for odors, tannins and discoloration.
• AquaClear 20 BioMax - ceramic media for the nitrifying bacteria colony.

Frequently Asked Questions

What aquarium size does the AquaClear 20 filter handle?

Fluval designs the AquaClear 20 for aquariums from 5 to 20 US gallons (18-76 L), in both freshwater and saltwater.

Can the AquaClear 20 be used in a saltwater aquarium?

Yes. Fluval rates the filter for freshwater and saltwater alike, which makes it handy as a supplemental or quarantine filter in marine aquariums.

Which filter media come with the AquaClear 20?

Each filter ships with AquaClear Foam, Activated Carbon and BioMax, covering mechanical, chemical and biological filtration.