Dual Flush Retrofit Kits - Has anyone installed/used them?

What are people saying about dual flush retrofit kits? Installation time? Do they work? Thanks,
Andy

My guess is that they won't work well. The goal of any toilet flush is to empty the bowl. Yes, you may not need as much water and momentum to empty the bowl with liquids only verses solids, but the flush has to be engineered to move all of the liquid, at least, out of the bowl. On toilets designed for this, they typically have a smaller amount of water in the bowl. A toilet not designed for this will have more. Trying to empty the bowl with less water than designed may end up leaving that water not replaced completely, and thus not flushing properly. Plus, if the suction was initiated, rather than just overflowing the bowl, there may not be enough water added to the tank to then refill the bowl. This would mean the next flush might not work properly, and need a second flush, adding to the water use, not saving it. With that in mind, you could try it, but depending on the cost of the valve, you might be better off replacing the toilet with one engineered to work that way.

When low flow toilets first became the law of the land, many manufacturers tried to use modifications to their old designs. These didn't work and the result was many people were lead to believe that the low flow concept meant frequent clogs and required regular plunging. Some of these companies are still trying this approach. Low flow toilets can and do work with as little as 1.28 gallons per flush if the toilet is designed to work with that small amount of water. Toto was and still is the leader in this technology. Patches just don't work.

Here is one that is around. I don't have hands on with it yet. Button linkage looks hokey.
http://www.gomjsi.com/