Waitrose have descaler in bottles for maybe £2 that have worked on my machine. If descaling doesn't work it could be the pump but since it is steaming (kind of??) then the pump might not be the cause as I found with the solenoid valve in the machine I got off Velocio: http://thehippy.net/nucleus/index.php?itemid=1233
Video of how to use your machine..
http://www.youtube.com/watch?v=RrBLyW_XlpU
Waitrose have descaler in bottles for maybe £2 that have worked on my machine. If descaling doesn't work it could be the pump but since it is steaming (kind of??) then the pump might not be the cause as I found with the solenoid valve in the machine I got off Velocio: http://thehippy.net/nucleus/index.php?itemid=1233