Find out if your swimming pool is leaking or if its just evaporation with the simple Bucket Test…Using an open top container such as a plastic juice pitcher you will sit the container inside of the pool such that it is partially filled with water. My preferred method is to use rocks in the bottom of the container and then sit the container on a stair or ladder step such that part of the container is below water level and part is above. You then add water into the container until the water inside the container and the water level in the pool are exactly the same. Wait 24 hours and then check to see if the water level in the pool is lower than the water level in the container. The difference between the two would be rate of water loss in your pool. If you do this test and the water level in the pool always matches the water level in the container then you do not have a leak in your pool – your water loss is a result of evaporation. Using a solar blanket at night over the pool will dramatically reduce how much water your pool loses through evaporation.
When you are doing the bucket test it would be a smart idea to record the weather patterns during this time period. The outside temperate (at both day and night) as well as cloud cover (direct sunlight the pool gets) as well as the amount of wind that you have. Most importantly you need to note if it rained or not as rain will likely invalidate your test results.