Knaus grey water tank

[nath130mx]

Hi guys, recently got a knaus 808 leg 2006 and on running the fresh water noticed it running straight out of the grey, had a look and it seems there is an adaptor missing, I cannot find anything that will fit in the gap as it looks like the thread is on the tank and it needs a male adaptor, there is a large red screw in cap the other side but this is sealed any help from knaus owners would be appreciated thanks

 

[mitzimad]

the red cap will come out you may need to tap it round with a peice of wood used like a chisel if there is a thread on the outside of the tank you just need to oppsite sex coupling a photo would help us advise