Hose properties
With one exception (SeaLand "OdorSafe" brand), white hose is more susceptible to odor permeation than black hose. The softer an more flexible it is, the more likely it is to permeate...the thicker and stiffer it is, the more resistant to permeation. However, configuration, toilet water useage and flushing habits can have as much impact on the life of any hose as its physical properties. For instance, the same Trident 148 white hose that was on one of my boats for more than 7 years without permeating took less than 90 days to permeate on the next boat. Black hose is more resistant to odor permeation than white hose, but it's not bullet-proof, either. Installation and whether waste is allowed to sit in it has as much impact on black hose as white. It may never permeate or only last a short time--longer than white hose would in the same installation, but how long it takes is as unpredictable as white hose.SeaLand "OdorSafe" is unique. There's a "skin" bonded to the outside of it made of a plastic material that's odor impermeable. That's what makes it "bulletproof" when it comes to permeation. It also makes it stiff as an ironing board, but no stiffer than heavy duty black hose. And not that much more expensive, either..and it's the only hose that isn't a crap shoot (no pun intended) when it comes to odor permation.