The water in the toilet tank is frozen so use the best way?

That can only be removed, placed in a plastic bag with more than two layers, and then placed in warm water, waiting to melt. Or leave it at a high temperature to melt.

If you don't use it, it's hard to get used to this behavior, so remind me more.

It is also possible to adjust the float in the toilet tank or put an object in it to take up space in the tank, for example, by placing a brick.

Yes, there may be cases where water from the toilet tank flows back into the mains. Under normal circumstances, the water in the toilet tank does not flow into the water supply pipe, because the pressure lever in the tank automatically crushes the valve when the water is full, preventing backflow. However, if the toilet bowl has been used for a long time, the valve is easy to break if it has been used for too long. >>>More

The ball plug of the tank does not seal the bottom of the tank tightly. >>>More