To see if water loss is from evaporation only, fill a 5 gallon bucket with water and place next to or inside the pool where it will get the same amount of sun as the pool. Mark the inside of the bucket and the liner at the water line. Recheck 24 to 48 hours later. Measure the distance between the water level and the bottom of the tape if the same amount of water is lost inside the bucket as inside the pool then the water loss is due to evaporation. Above ground pools are easily repaired with patches that are applied under water. Patch kits are available at the Above Ground Pool & Spa Company in San Antonio, Texas.