25' from head to tank is WAY too far!
About 6' is the max distance that bowl contents will move in the amount of time 99% of people will spend pumping a manual toilet or leave their finger on a flush button...10' is the absolute max that anyone can be "retrained"...and flushing long enough to move it that far will fill up the tank with flush water. And unless bowl contents make it all the way through the system--and the hose is rinsed out behind it too--it sits in the hose. And it's waste left sitting in hose that results in stinky hose.That's the long version of the answer to your question "how long should a hose last." The short answer is, in a 25' discharge line you'd be lucky if you only have to replace any hose made every 5-6 years. What you really need is a second tank that's a LOT closer to your forward head.That said, the best sanitation hose available now is Trident 101/102 (same identical hose, just different colors).http://www.tridentmarine.com/stage/sanitation.htm For more details, check my posts for the last couple of weeks...I've discussed it several times.How long it takes any hose to permeate is determined by how