Also, make sure that the refill hose is directed into the overflow riser and daylighted above it on a clip. If it isn't, then you are getting NO refill water. The refill hose is connected to the fill valve, and, as I say, should run over to and dump into the overflow riser.
Here's what the process should look like:
If you have the valve with the white screw on it, turn the screw to adjust the water level. If you have one without the screw, like the one in the video, let me know and I will give you the instructions.
Let us know whether this works. If it doesn't, there are other potential problems but this one is the most likely.