Hi Folks, Background: My pond is approx 1100 gallons, and about 12 feet diameter and knee high. There is a epdm liner. The oase pump is connected via a hose to an external bio filter that falls back into the pond. And we live in Virginia, so we do have high temperatures in the summer. There is an old bottom drain at the bottom that we never use. What happens is that after I top off the pond with the garden hose, the water level drops down 3 or 4 inches by the next day. The water level just always drops to below the rocks that edge the pond. Is this a leak or just evaporation? How many inches of water is normal evaporation loss - during a summer day or any day? thanks!