yeah that inlet connection is a tight right turn.
try using a 3-5 foot 'leader' hose instead of that 18 inch version.
and a slightly more flexible/pliable hose material.
with a longer connector hose, it can be feed out the hole on the right side for connecting the main hose/filter.
then turn ON the water, check for drips, good seal and so on.
the access hatch will then close without pinching the connector at the inlet.
i fiddled with Ys and elbows and quik connects and other ideas at the inlet without satisfaction.
the 3-5 ft connecting hose has worked out the best.
this remains connected 24/7 and pulls back through the hole to loop around in that compartment.
along with 25 ft of COILed fresh water hose.
all of the true things that i am about to tell you are shameless lies. l.b.j.
we are here on earth to fart around. don't let anybody tell you any different. k.v.