Information on CO2-carrying hoses: Not every material is suitable for conducting CO2 gas, because many plastics are suitable for air but are permeable to CO2 gas. This is because CO2 diffuses differently to air. That’s why air hoses are unsuitable for CO2 systems. The plastic used for JBL PROFLORA T3 hoses is suitable for CO2 and fits all common CO2 systems.
Install the hose connections so that they are as short as possible. The shorter the CO2-carrying hoses, the faster the whole system will react when you increase or decrease the pressure at the fine needle valve. But even with short hoses your settings will always have a delayed reaction. So don't wildly turn the fine needle valve of the pressure reducer: adjust it slightly and wait a little before the number of bubbles in the bubble counter (JBL PROFLORA COUNTSAFE) changes.
CO2 hoses also harden over time and should then be replaced. JBL offers special CO2-resistant hoses: JBL PROFLORA T3.