Ultum Nature Systems Pro Inline CO2 Diffuser, 16mm Space Gray Aluminium

The Ultum Nature Systems Pro Inline CO2 Diffuser is an external diffuser for freshwater planted aquariums, designed to diffuse CO2 through a filter return line, with a side-mounted ceramic plate and a 16mm model for compatible tubing.

• Installs on the filter return line outside the aquarium — keeps a bulky diffuser out of the tank.
• Side-mounted ceramic plate — diffuses CO2 while allowing strong water flow.
• Aluminum construction in Space Gray — made with corrosion-resistant aluminum.
• Three model sizes: 12mm, 16mm and 20mm — choose a size for your canister-filter setup.
• Accessible ceramic plate — supports cleaning or replacement without disconnecting the full system.

For a planted aquarium, CO2 diffusion can be part of the tank setup, but an in-tank diffuser takes up space inside the aquascape. This inline design places the diffuser outside the aquarium on the filter’s return line. It is made for aquarists using a canister filter who want to keep the equipment inside the tank less visually prominent.

How does the Pro Inline CO2 Diffuser fit into an aquarium setup?

The diffuser installs outside the aquarium on the canister filter’s return line, so it does not sit among plants and aquascaping hardscape. Water passes through the return line while the side-mounted ceramic plate diffuses CO2. Its design is intended to support strong water flow without clogging the output.

• External placement keeps the diffuser out of the aquarium.
• Compatible size options include models for UNS Delta and Blitz filters.

Which tubing size is right for this model?

This version is the 16mm model, made for 5/8 in (16 mm) or 16 ID tubing. Ultum Nature Systems also offers 12mm and 20mm models, so the size choice depends on the tubing used in your canister-filter setup. Match the tubing size before choosing a model.

• Selected model: 16mm.
• Other available sizes: 12mm and 20mm.

How do you access the ceramic plate for maintenance?

The ceramic plate can be reached for routine cleaning or replacement without disconnecting the full filter system. This access is useful when maintaining the diffuser as part of regular aquarium equipment care. The aluminum body has a Space Gray finish and is made from corrosion-resistant aluminum.

• Plate access supports cleaning and replacement.
• No need to disconnect the full system to access the plate.

The Pro Inline CO2 Diffuser suits freshwater planted-aquarium owners with a compatible canister-filter return line who want external CO2 diffusion and less equipment inside the tank. The 16mm version fits the specified tubing size and uses an accessible ceramic plate for maintenance.

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