The Slooooooow Flush
To make best use of the following slow flush help page you need to know whether water isn't getting into the bowl fast enough or isn't getting out fast enough.
Take a bucket of water and dump it quickly into the toilet bowl. If it flushes normally (like when you flush a working toilet), water is not getting from the tank INTO THE BOWL fast enough. If it doesn't flush normally, water probably isn't getting OUT fast enough.