I have never used one before, but in my opinion, it looks utter rubbish. You may well struggle to keep the CO2 stable. Provided your tank is low enough light, go for the liquid carbon source. On a tank your size, pressurised CO2 would be the preferable choice.
They have those kits in maidenhead aquatics and i would have to agree with Dave they look to be insufficient for your needs, i would go with a JBL D&D set if you dont want to go for the full fire extenguisher route, may be more expensive than the one in your post but at least you are getting decent kit with it.