James Marshall
Member
- Joined
- 14 May 2009
- Messages
- 316
Here are the plans for the inline CO2 diffuser I recently built


In practise the design seems fairly effective, and is more efficient at dissolving and distributing CO2 than other diffusers I have used.
The design does not differ greatly from some of the DIY diffusers I have seen. However, it is simple to construct with no drilling, sawing or gluing required, and it improves contact time between water and bubble by spinning the water inside the reaction chamber. The spinning effect is produced by inserting an Eheim lock nut into the hose (as shown in the diagram). After an about an hour of running, the internal screw thread of the lock nut will create a small vortex , not the raging vortex of terror I had hoped for, but it does increase contact time.
For my 20 litre tank a reaction chamber length of 25cm is sufficient, for larger systems simply increase the length.
I hope this is useful
Regards James


In practise the design seems fairly effective, and is more efficient at dissolving and distributing CO2 than other diffusers I have used.
The design does not differ greatly from some of the DIY diffusers I have seen. However, it is simple to construct with no drilling, sawing or gluing required, and it improves contact time between water and bubble by spinning the water inside the reaction chamber. The spinning effect is produced by inserting an Eheim lock nut into the hose (as shown in the diagram). After an about an hour of running, the internal screw thread of the lock nut will create a small vortex , not the raging vortex of terror I had hoped for, but it does increase contact time.
For my 20 litre tank a reaction chamber length of 25cm is sufficient, for larger systems simply increase the length.
I hope this is useful
Regards James