Both above ground and in-ground pool owners will face the issue of water level height at some point in their ownership. Although it's easier to manage the water height in the pool than to balance chemicals and maintain a filter, it's still a critical component of pool maintenance that you should not overlook.
Many pool professionals collectively agree that the pool water height on both an in-ground and above ground pool should be at the vertical mid-point of the pool skimmer. The skimmer is responsible for providing a channel for the filter to suck in the water to be cleaned. Water enters the skimmer and moves to the filter via a pool hose and back out the return jet. The skimmer is also a resting place for larger pieces of dirt and debris that are blocked by a skimmer basket.
If the water height is too high, the large pieces of debris such as leaves will float back out of the skimmer basket and into the pool. The skimmer shouldn't be completely filled with water. The filter operates better when the skimmer opening is only half full of water. When the water level is below the skimmer it can permanently damage the filter and its motor. The filter is not designed to suck in just air but needs the proper flow of water to work efficiently.
Based on the potential problems the lack of water can present to the filter, pool professionals agree that too much water is a less severe problem than an insufficient amount. The more you use the pool, the better chance you have of losing water to splashing pool swimmers. Evaporation is also a cause for water loss, as is vacuuming to waste, backwashing, liner leaks, filter component leaks and exceedingly high temperatures. Fill the pool up immediately and turn off the filter if the water level falls at or below the bottom of the skimmer.
Pool owners can fill the water up with a standard garden hose but if you forget the hose is on, walk away and the pool starts to overflow, there is not much you can do. Once the water stops spilling over and flooding your yard, you can use your filter to continue draining the water until it reaches the mid-point of the skimmer.
Backwashing your filter in the "drain" setting is probably the easiest and cleanest way of emptying the pool a little off the top. Attach a pool hose to the filter and lead it to your nearest drain. Allow the water to return to it normal height and resume normal filter operation.