After a flush I measured the amount of water that comes out the fill tube during a flush and it is over half a gallon. So add that to the water that gets dumped into the bowl during a flush and this just shouldnt be a problem. The fill tube is solidly attached to the overflow tube and I have verified that 100% of the water from the fill tube is going down the overfill tube. I have no idea where all that water is going; its not on the floor and its not in the bowl so somehow I guess its going down the sewer?
Now, I did notice that where the tank sits onto the bowl platform, that inside where the bowl receives the tank water during a flush, right there in the bowl there does seem to be 2 different ways for water to run, does one of those paths just go straight to the sewer, bypassing the bowl? If so then I guess all my water from the fill tube going down the overflow tube could somehow be directing a lot of that water from the fill tube straight into the sewer? Just a guess?
So thats where we're at now. I had a leaking flapper so I got the "Fluidmaster Performax 3 in. Universal High Performance Everything Toilet Repair Kit with Install Tools" from Home Depot and installing it was a breeze. But after reading 100% of the instructions and adjusting every possible setting I still need help adjusting the water level in the lower bowl as now there is very little water in the bowl after a flush, much less than before I replaced the flapper. I've looked at all the instructions and have adjusted every setting so that the fill valve is open for a very long time during a flush, and have also turned up the refill tube adjustment to the max possible volume of water.
Where is the fill tube water going?