JOhnH
Touchdown! Greaser!
That is my thought too, unless he is topping it off every time it goes down a quarter inch. Time for a bucket test.You've got a leak somewhere.
Put a rock in the bucket to keep it from floating away.
Put the bucket on a step and fill it to the same level as the pool.
After a few days, the level in the bucket should still be the same level as the pool.