The following:
- Timer to turn CO2 on 2 hours before lights come on and 1 hour before lights go off.
- CO2 proof tubing.
- Some form of CO2 injection eg in line diffuser, reactor etc.
- Ensuring your filtration rate for a 240litre tank is at least 2400litre/hour (x10 rule of thumb).
- Controllable lights to keep lighting levels under control. I assume you have already, as you say planted tank.
- Drop checker & indicator to determine CO2 levels.
- pH pen, can be useful as well for determining CO2 levels.
- Patience to set up CO2 injection rate to achieve 30ppm at lights on.