Currently breather is plumbed to
anchor locker. I suspect I can keep that arrangement, as it is easy to access with a hose.
From the tank end, the breather hose is 16mm (~5/8") reinforced water hose for most of the run and then is coupled into a short piece of white, spiral reinforced sanitation hose (19mm 3/4") to the filter and from the filter to the actual vent.
Could replace entire run with either 16mm reinforced water hose or 19mm sanitation hose, with a 16mm to 19mm adapter at the tank end. Sanitation hose doesn't seem to come in 16mm. While I note some say 1 inch is better, in the end air flow is constrained by narrowest point, which is whatever the inside diameter of the 16mm vent fitting on the tank is.
Rest of the waste plumbing (as opposed to
flushing water plumbing) is in 38mm (1.5 inch) sanitation hose. with an anti-syphon loop in the
overboard line.
I don't know if the waste plumbing has been permeated (still need to do the rag in hot water test). There is a type of 38mm sanitation hose that is
sold here as impermeable, guaranteed for 5 years, "...tube is made out of a special butyl rubber compound, this avoids odour spread and algae formation which is the cause of flora bacteria growth". Any experience of that? I know the answer is to have aerobic bacteria, so no odour in the first place, but is it worth, as
insurance, also having impermeable hose? It costs a tidy $AU 85 / metre ($US53, Euro 51 and GBP 43) , and I'd need maybe 5 or 6 metres, but if it really works...
Also any recommendations on tank sender units? I don't have a gauge currently so it's guess
work as to how full the tank is.