A dual flush conversion kit for toilets -- saving water.
The problem with existing toilets and existing drainage systems is that they were designed and tested using lots of water. When we try to reduce the water in the existing toilet it may not even get the solid waste out of the bowl. Even when we install a good low flush toilet but on an old drainage system that has an occasional history of plugging up or not flushing properly before the change, we are asking for trouble.
But we all know that we don't need all that water every time we use the toilet -- as is attested to by the instruction sheets on the walls of all cottage toilets.
So a fellow out in British Columbia had the genius idea of breaking with plumbing tradition and building a two flapper tank stack. The first flapper is just slightly higher than a traditional one, but this does leave a bit more water in the tank than a regular tower. Using a full 2/3rds of the water in the tank does give a good flush in almost all toilets. The 1/3rd tank of room temperature water that remains helps to keep the tank from sweating in the summer time. When there is not much solid waste, then you can use the smaller handle and activate just the upper flapper, which will flush only 1/3rd of the water from the tank, a real water savings. And since there are a lot more small flushes than big flushes, the room temperature water in the tank tempers the incoming cold water to further prevent the sweating problem.
So with this simple retrofit to any toilet tank, you can save a significant amount of water, still get a full sanitary flush when you need it, and prevent most if not all of the sweating on the tank in the summer. For people on a septic system using well water, this is a double blessing.
Of course the hardware stores all said that it was far too complicated to sell, so our genius inventor in Vancouver couldn't get this Dual Flush to market. We carried it for a while in my store because I love this thing but have finally dropped because of several such issues, but mainly because the manufacturer had difficulty to fulfil orders on a timely basis. Another issue was that many of our buyers found the installation to be too difficult. You have to remove the tank from the back of the toilet to make this installation. As well, many toilets required one more replacement gasket than was in the kit, an extra trip to the plumbing store -- frustrating. The double handle and arms needed some bending to work well on curved tank faces.
Of course, these water conservation devices will not work when added to already low flush toilets. There isn't enough water in a low flush toilet reservoir to work with this device. Some people don't realize they already have low flush toilets, and dual flush on a siphon action low flush won't work. (See "toilets" in the database for Australian "wash down" low flush dual flush toilets that do work.) So for those of you who are looking for the Dual Flush retrofit, that is why it is no longer in the stores.