Help finding baffling leak

[book of kells]

Split by moderator from HERE. jblizzle

We are baffled-last winter we lost half the water in the pool before any freeze, and could not keep the level up after refilling, so figured we had a leak that we would find when we open the pool for the summer. guess what..opened the pool, refilled it and no leak, the water level stayed normal (given evaporation). We covered the pool last month, and now the water level is going down again, by a lot, much faster than could be explained by evaporation. There is no sign of leakage outside the pool, and the water level is beneath the skimmer and hose outlets.
What are we dealing with? We are in Long Island NY, and the weather has been very mild with little rain.
oops I'm a newbie! forgot to mention this is a above-ground pool, 24 x 52, about 6 years old

 

[X-PertPool]

unless it has a main drain you probably just have a leak you attribute to evaporation during the summer. but once there is a lid on the pool and it can't evaporate or be refilled is when you notice the loss. you can hire a leak detection company or just change out the liner.

 

[linen]

Welcome to tfp, book of kells

I agree with X-pert, evaporation probably masked the leak. Did you try the bucket test?:http://www.troublefreepool.com/pool-school/leak_detection

 

[Leak Specialist]

In ground pools are bad about getting very small pin holes.

These pin holes sometimes leave little divots in the bottom of the pool.

They are also small enough to get plugged by almost anything, pollen for example.