Why does the loo pong?
QWhy do we get an awful smell come back up when we use our pump-out toilet.
BARRY3DOVE, from the CB website
ATONY REPLIES… The technical answer is because you have let the anaerobic bacteria breed at the expense of the aerobic ones. Both types break down the waste, but the aerobic create far less smell. Another problem that can occur is that the tank does not hold enough liquid to submerge the solids.
As you do not specify the type or model, by saying ‘come back up’ makes me think this is probably a simple dump-through. If you are using conventional ‘blue’ it can kill the somewhat weaker aerobic bacteria, so change to a biological holding tank treatment.
You will need to give the tank a really good flush and then put up with a period of smell while the remaining blue is purged from the system and the aerobic bacteria gets established. Choose a treatment that says it contains bacteria and enzymes.
You also need a flow of air over the effluent. Ideally a breather at each end of the tank with an internal diameter of not less than one inch, but the larger the better. If you have a macerator or vacuum toilet you might also have a charcoal filter on the breather. These can trap smells from the breather but stop air reaching the tank. In the summer you might well have to pump out every week but in the cooler months I find I can go for weeks between pump-outs.
Try putting some yoghurt down the toilet when you first change from conventional blue to seed the bacteria. Some people swear by just adding yeast to the tank, others use septic tank treatment. Other additives are Biomagic, Odourloss and The New Blue Loo Company.