CO2 diffuser booster

This improves efficiency of the EHEIM CO2-SET Diffuser 400l by connecting it to an external filter outlet. (https://eheim.com/en_GB/complement/accessories/co2-diffusor-400).

The original diffuser works, but some of the bubbles are quite large and won't get dissolved.

This thing is connected to the outlet of an external filter or other pump. The water flows over the diffuser stone at relatively high speed and drags the CO2 along in the shape of very small, mostly invisible, bubbles.

Fits the 30 mm round diffuser and 12 mm (i.d.) hose. Use for instance zip tie, rubber band or fishing line to tie it all together.

*WARNING!* The booster could possibly increase the risk of water getting siphoned backways if the CO2 line looses pressure (e.g. during bottle change) - take precautions:
- Disconnect the diffuser when doing maintenance on the CO2 side
- Use double check valves on the CO2 line
- Perhaps keep the fish tank in the bathroom!