Here is the problems I found with my KZ:
1. Most of the fresh water spilled out the vents when traveling on curvy roads.
2. The supply port was above the bottom of the tank so that about 20% was not accessed.
3. The tank was supported by only three straps causing downward sagging that wasted capacity.
To fix these problems, the vents were moved to a level above the tank, the supply was moved to the drain port and two straps were added to reduce sagging.
Make sure that your trailer frame is level side to side and front to back. Don't take the advice about leveling any other way. A water tank is usually very short in height and even an inch out of level is a lot of water.