Rinse diffuser with warm water. Attach suction cup and desired tubing (Compatible with 6 mm (1/4") - Standard Airline Tubing) to the diffuser.
To attach tubing to diffuser, wet the inside of the tubing with water at the attachment point and carefully slide tubing over diffuser stem. To avoid breakage when removing tubing, do not pull tubing off of diffuser. Instead, cut tubing carefully along the attachment length to release the diffuser.
Mount your diffuser using the suction cup(s). It should be positioned low in the aquarium. When removing or repositioning the diffuser, pull by the suction cup(s) rather than the diffuser stem to avoid breakage.
Install check valve (not included) inline with tubing outside of the aquarium
Once securely mounted, turn on CO2. Observe bubble count and adjust CO2 to desired flow rate.