Help!

I have the "standard" NACA ducts on the side of the fuselage for cabin fresh
air vents.  These NACA ducts each have two CAT hoses going to panel mounted
eyeball vents.

My wife is getting really tired of having to spot treat my shirts for rust.
After rain, the water pools in a low spot in the hose (the low spot is
unavoidable), and then becomes rust water after a few days of reacting with
the metal spiral core of the hose.  When I open the eyeball vent for fresh
air I get blasted with a nice coating of mucky brown rust water.

Any suggestions?  I've tried to locate the black platic looking hose on
hopes that the metal is better sealed than the SCAT that I am using.  Would
SCAT work better or would the water still find its way to the metal spiral?
I also found this stuff
(http://www.flexfab.com/Products/Aerospace/Lightweight-ducting/ultra.htm)
but they don't sell to individuals or in small quantities.

Any suggestions will be appreciated,

Matt