My uberhaus toilet does not have enamail on the bottom of the bowl so it is impossible to remove the stains. Any solution without having to return the toilet itself.

SOURCE: New Pegasus Dual Flush Toilet Water does not enter Toilet bowl

There is a small plastic tube that comes from the fill valve and attaches onto the overflow tube on the flush valve. If no water is coming out of that tube, then it is clogged internally. You can remove the tube from the fill valve and take a small piece of wire or a straight pin to try and clear it from the outside. If that doesn't work, then I would recommend replacing the fill valve. They are inexpensive to replace. If you don't know how to get into the fill valve's internal guts at the top, then I would recommend replacement of the valve. One more thing, there also could be a water saver where the outlet is on the little tube I just explained. It is usually light blue, you can remove that and discard it.

SOURCE: correct tank to bowl gasket for Orion toilet

I would change out the flush valve itself...it will come with the right gasket....it won't cost anywhere near the price of a new toilet...and it will save you time in the long run..good luck and.thanks for rating my effort....the fang.

SOURCE: toilet bowl gurgles after flushing cycle

Sounds like your toilet is not vented properly. Possilbly something caught in the trap is causing it to syphon

SOURCE: Aquia II Dual Flush Toilet: toilet after flush removes to much water from bowl...

Adjust the float on the Fluid-master a little higher if possible. This should allow more water to enter the bowl after the flush.

SOURCE: We have a Jacuzzi X532 toilet. Can't get the water

I am not familiar with the model of toilet that you have, but many toilets suffer the same problem. It is usually due to the toilet cistern over-filling, as the water running into the bowl is the safety-overflow mechanism. The overfilling can be for a few reasons. The most common is that the fill valve is being held open, either due to mal-adjustment, or due to it being postioned slightly wrongly so that it hits either the side of the cistern or another part of the mechanism and can't close off properly. If you lift off the top of the cistern and watch what happens when the flush goes, you might be able to spot what is preventing the valve from shutting off entirely, and solve it. Hope this helps! :)