Juwel Rio 180 Filter...

[sammclean23]

Hi All,
 
seriously getting frustrating now, can anyone please advise how to fit the air diffuser/directional tubing for this filter?
 
it seems obvious here:
 
https/www.google.co.uk/search?q=juwel+rio+180+filter&bav=on.2,or.r_cp.r_qf.&bvm=bv.52109249,bs.1,d.Yms,pv.xjs.s.en_US.e7W6Chm7DWQ.O&biw=1745&bih=905&dpr=1&um=1&ie=UTF-8&hl=en&tbm=isch&source=og&sa=N&tab=wi&ei=upIwUvyaGMrB7AaXxYD4Cw#hl=en&q=juwel+rio+180+air+diffuser&tbm=isch&um=1&facrc=_&imgdii=_&imgrc=7F8rq9TzUPxC-M%3A%3BgN4IBMF88aq5DM%3Bhttp%253A%252F%252Fwww.juwel-aquarium.de%252Fout%252Fpictures%252Fmaster%252Fproduct%252Fmain%252Fzoom%252F1%252F87050.jpg%3Bhttp%253A%252F%252Fwww.juwel-aquarium.de%252Fen%252FProducts%252FMore%252FFiltration%252FFiltersystems%252F%3B863%3B863
 
Though my filter head is different in that it does not have a gap to hold the tubing in.
 
Also, the instructions with the tank describe a much different head, although mine is a Juwel head and fits as pictured.
 
Can anyone please clear this up as after a long search online, I cannot find an answer anywhere!
 
Thank you