The book is written by an American for the US market, but the principles it describes and explains are the same for marine toilet systems anywhere.  Peggie Hall is one of the USA's acknowledged experts (there aren't many!) on marine sanitation. She writes in a clear, direct style on the principles that govern the behaviour of microbes in dark, wet places, and how to keep them under control. In brief outline, Peggie Hall's book says:

1. Know the law. Toilet waste discharge is illegal in US (and UK) inland and coastal waters. Ask your harbourmaster, marina manager, cruising association, sailing club or river authority about the regulations. (The leading UK boating magazines have databases on boating matters of every kind, and will often help if you ask nicely).

2. Make sure that your toilet system can stand up to the movement and shocks of marine use. Every part of the system needs to be accessible for maintenance and repair.

3. The way to avoid foul smells is to design the toilet system so that air can circulate through it.

4. Train yourself and your crew to flush the toilet efficiently.

5. Cleaning substances made and sold specifically for marine toilets can be useful in a well-designed system. See 3 above. To clean your toilet we recommend 'Toilet Fresh Clean and Condition'

6. Prevention is better than cure. Change the rubber parts in the toilet at least every two years.