We had a bladder on a previous boat. I was washing it one day and the bilge pump kicked on, which had never happened before. I smelled it before I saw it. The PO had patched a hole on the underside of the bladder, which failed. We replaced the bladder with another bladder and never had an issue, but I have to advise against ever patching a bladder.
The problem with using a bladder tank for holding sewage is that you are creating an anaerobic environment, which is even nastier than what normally breeds in there. Nobody likes to think about venting a holding tank but it's actually very important for multiple reasons including microbiology and for pumping in or out.
If you buy the good ones, they are incredibly tough. The Army drops "big plastic bags" of diesel fuel to mech troops in the desert. Yes they drop them low and slow but I think your average tank would not do as well plummeting from a C130.
Mixed reviews on that. I only had two. One sprung a leak after a couple of years (on a seam of course) and one was fine until long after I sold it. But they also were prone to microbiology problems if you recall... and I don't mean the sheets...I based my attitude on experiences with waterbeds in the 70's.
Yep. Always use cheap stuff for the prototype. Especially if you're like me and get to the Mk 3 (or later) version before you're happy with it.
