Subject: Pool Water Level
For your pool to run smoothly, the water level must be just right. The swimming pool skimmers operate best when the water level is at least one third to half way up the skimmer opening. 
If the water level is too high, it can potentially get behind the liner of the pool, or overflow with swimmers in the water. If it is too high, the debris will not be able to float into the skimmer, and they will not work correctly and the debris passing by will eventually sink, causing a dirty pool floor.
If the water level is too high, it can potentially get behind the liner of the pool, or overflow with swimmers in the water. If it is too high, the debris will not be able to float into the skimmer, and they will not work correctly and the debris passing by will eventually sink, causing a dirty pool floor.
If the water level is too low, air will be sucked into the system through the skimmers and can cause the pump to lose its prime and eventually lead to a burnt up circulation system.
Remember to always add water to your pool BEFORE vacuuming or backwashing as those will lower the water level.