Seachem Glass CO2 Inline Diffuser 13mm Global recommendation The built-in bubble counter allows

The built-in bubble counter allows for easy monitoring of the rate of CO2 injection

have a look at the Colombo CO2 Reactor or Tropica CO2 Nano System

high range pH

If you want to avoid this

Mix Bio CO2 powder with 300 ml water and let it rest for 24h

Seachem Glass CO2 Inline Diffuser 13mm Global recommendation The built-in bubble counter allowsMinimizes the visibility of CO2 equipment in the aquarium Ensures maximum dissolution of CO2 in aquarium water Allows for more consistent dosing of CO2 Compatible with 12 mm ID 16 mm OD hoses The 13 mm glass Inline Diffuser is a pollen style inline CO2 diffuser that is placed in the outflow line of the filter or aquarium pump to efficiently diffuse CO2 gas into the aquarium. This placement of the diffuser avoids the need for a diffuser in the aquarium