I was perusing ebay yesterday, as you do, and noticed this little CO2 set from the ebay seller AAS: http://cgi.ebay.co.uk/ws/eBayISAPI.dll? ... 0048117525 I thought it looked quite interesting! Â£34 including shipping doesn't sound too awful either, its just whether the CO2 cartridge can be replaced easily or not, though they do sell spares at a "reasonable" price: http://cgi.ebay.com/ws/eBayISAPI.dll?Vi ... 0048145536 I've found somewhere that sells catridges, which I think might be the same, though need to do some research, and they are very cheap: http://www.co2cartridges.co.uk/eu/prod_288.html/ I'm sure I could find cheaper too. Its all a case of knowing the thread size I guess. I'm pondering if I should get a set for my little 1.5l nano tank. Any thoughts?