We're on a Bavaria 40 (2002 model) and it has two 10-Gallon (40 liter) holding tanks- one in each head. They are both gravity-draining. We are a family of 3 living aboard and are finding that the tanks aren't big enough (we get a pump out service 1x a week). We are thinking of replacing the aft holding tank with a bigger one since it is in the lazarette (we're in a twin-cabin model). Does anyone have any experience doing this? No idea what type of tank would work, etc. Also, we realize that we will need some holding tank monitors so we know what's in there.... I miss my compostable toilet on my old boat! LOL
Call these guys, used them before. They are really good. Lots of help and advice.
http://www.tek-tanks.com/boattanks/sanitation-systems/holding-tanks/
Hope this is of use.
Best regsrds.
Ant
After some 'unfortunate' incidents with our holding tank on our B36 I investigated getting a level indicator. There is a huge choice out there and, although we did not get one in the end, we did conclude that no part of the gauge should be inside the tank and definitely nothing mechanical! They all seem easy to instal but at a wide variety of costs.
Look at Gobius for tank monitors.
Robgs