We just purchased a low-volume (1.6 gpf) toilet that has a bowl shape that is very shallow in the front. Because of the bowl shape and low amount of water in the bowl, it must be flushed twice to clean the front edge of the bowl. Now it is a 3.2 gpf toilet. Question: How can you raise the amount of water in the bowl?
Due to the trap configuration and design of 1.6 gpf toilets the volume of water in the bowl can not be adjusted. It sounds like you may have purchased a cheap toilet. The old adage of you get what you pay for certainly holds true with low flush toilets.