Ultum Nature Systems Pro Inline CO2 Diffuser, 20mm Space Gray Aluminium for Aquariums

Ultum Nature Systems Pro Inline CO2 Diffuser is a 20mm aluminum diffuser for adding CO2 to a freshwater aquarium through the filter return line, with a side-mounted ceramic plate designed to maintain water flow.

• Installs outside the aquarium — keeps bulky diffuser hardware out of the aquascape.
• 20mm model for 25/32 in (19.84 mm), 13/16 in (20.64 mm), or 20ID tubing — matches specified canister filter tubing sizes.
• Side-mounted ceramic plate — diffuses CO2 without restricting output flow.
• Space gray aluminum body — made from corrosion-resistant aluminum for a planted tank setup.
• Accessible ceramic plate — supports routine cleaning or replacement without disconnecting the full system.

Planted freshwater tanks need a way to introduce CO2 while keeping equipment from taking up space inside the aquarium. This inline design fits on the filter return line, so the diffuser sits outside the tank rather than among plants and hardscape. It is made for aquascapers using a canister filter setup who want CO2 diffusion integrated into the return path.

Does the diffuser sit inside the aquarium?

No. The Ultum Nature Systems Pro Inline CO2 Diffuser installs outside the aquarium on the filter’s return line. That placement removes the need for a bulky diffuser inside the tank and keeps the aquascape clear of this piece of equipment. The 20mm model is also compatible with UNS Delta and Blitz filters.

• Designed for freshwater aquarium use.
• Part of an inline canister filter setup.

Which tubing fits this 20mm model?

The Ultum Nature Systems Pro Inline CO2 Diffuser in 20mm fits 25/32 in (19.84 mm), 13/16 in (20.64 mm), or 20ID tubing. Compare your filter tubing with these listed sizes when choosing the model. The product family is available in 12mm, 16mm, and 20mm sizes; this listing is for the 20mm version.

• Specified tubing options: 25/32 in, 13/16 in, or 20ID.
• Other available diffuser sizes: 12mm and 16mm.

How does it diffuse CO2 without restricting the return flow?

The Ultum Nature Systems Pro Inline CO2 Diffuser uses a side-mounted ceramic plate for CO2 diffusion. Its design is intended to support efficient diffusion while allowing strong water flow through the filter output without clogging it. The body is aluminum with a space gray finish.

• Side-mounted ceramic diffusion plate.
• Corrosion-resistant aluminum construction.

Can the ceramic plate be cleaned or replaced?

Yes. The Ultum Nature Systems Pro Inline CO2 Diffuser provides access to its ceramic plate for routine cleaning or replacement. The plate can be reached without disconnecting the full system, making these maintenance tasks more straightforward.

• Plate access is designed for maintenance.
• The ceramic plate can be replaced.

This diffuser suits freshwater aquascapers with a compatible canister filter who want CO2 diffusion on the return line and less equipment inside the aquarium. Its 20mm size, external placement, and accessible ceramic plate make it a fit for planted tank setups using the specified tubing.

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