Loosing water very fast

[satellitester]

Hello everyone,
Last weekend I opened up my in ground pool. Since then the water level dropped significantly. Here is the sequence of events.

Last Saturday I put water pump on the turpentine cover to remove water from it. The water level was about one feet from the ground level. Pump run for about 2 hours then it started to rain, so I shut off the pump and went inside. It rained all night. However, in the morning I was surprised to see that all water is gone from the cover and the level dropped to about two feet from the ground level. At first I thought, eh... no big deal, probably "communicating vessels", as it looked like the other end of the hose was lower then the pump on the turp. Then I removed the cover, started water pump, dumped 18 gallons of chlorine in the pool, connected leaf bagger and started collecting leafs. After I was done with the leafs, I left water hose running to full up the pool.
On Monday, I noticed water level dropped because skimmer was making noise by sucking the air. I refilled the pool with water and had water pump off over night.
Here is a picture I took Tuesday morning.



This is how it looks today.



Also note wrinkles, it didn't look anything like that when I pulled off the cover.






I was suspecting plumbing, but as the water level dropped below the return jets doesn't seem to be the case. I can't see any obvious damage to the lining.

TF-100 kit says chemistry looks as follows:

CL <.5
pH 7.3 - 7.5
TA: 50
CH: 40

Please advise.

 

[OldPoolMan]

The fast way to diagnose a pool leak is a bucket test. It's pretty foolproof. Turn everything off. Mark the water level in the pool. Find a large bucket, no leaks, fill and mark it's water level Use a large bucket like a 25lb 3" tab bucket. Wait 24 hours and compare water levels. If the pool level is less than the bucket, you have a leak. Of course, rain, or a dog drinking from the bucket would dis the test.

 

[poolnoob.ca]

you really put in 18 gallons of chlorine at once? seems like too much, whats your pool volume?

 

[suzook]

Wow! That's a lot of water to lose. You have a serious hole somewhere. Maybe main drain.

 

[duraleigh]

That's a pretty robust leak. I would continue to let it drain to see where it stops. If it is still leaking when there is only 6-8 inches in the shallow end, I would start to refill so your pool doesn't get too low and call a leak detection guy if you don't finds it by then.