I have the MIDI dust ex. and just got the Domino 500 but the dust hose will not connect and not founding an adapter that makes sense.
Any advise, thanks.
The hose that comes with the Midi I should have the 27mm tool end on there and that slips right onto the DF 500 dust port. If that's not working for you, something ain't quite right. Post a picture of your hose and collection point on the 500.
Literally the first time I used my Domino 500 was with a MIDI I with the stock hose, so I'm 99% certain they're compatible. As others have said, the collection can be a pain to put on. Page 12 of the manual that's in my Systainer has tips on how to attach the hose, but they show the old style of collection port, not the new twist-lock.
For the twist-lock, line the arrow on the hose nozzle up with the line on the collector port of the Domino. Force it on to the port, then twist clockwise to line the arrow of the nozzle up with the arrow on the port. To remove, reverse the steps.