Multi-flush toilet problems

Previously I discovered that my old 13G toilet can use as little water as new dual flush toilets, and maybe even less, because I have 2nd chances.

The adjustable flappers can reduce the water usage but maintain powerful flush. The problem is the refilling of the toilet bowl. Because less water is used, the tank refills faster, but the toilet bowl do not have enough time to refill, about an inch or less water level. This lead to very poor flush. Because of the poor flush, the toilet bowl will still be full after flush. So the next flush will be perfect. I call this odd-even flush phenomena.

You still save water if you need to flush twice for the even flush. Sadly no conventional valve can be adjusted to refill faster.

My experiment is to siphon water from the tank down the toilet bowl continuously with a driper. My estimate is that about 10 liter of water is wasted per day this way. So it is equivalent to a few flushes. So if the toilet is used a few times a day it will break even. The problem is having enough time in between flushes for the bowl to refill.