Good morning, 
 
We have just had a concrete pool installed. We have been using the pool for around 3 weeks now. On Saturday our pool was loosing water but stopped at the bottom of the skimmer box. We topped the pool up and again the next day the same thing happened. We got our pool man back and he has dug up all our newly planted back garden around the pool trying to find the leak. There is no apparent place where over 30,000 litres of water has gone. The pipes aren't leaking the actual skimmer box is not leaking and we are all at a loss as to where all this water has gone. Last night we again topped the pool up and this morning the water level hasn't moved an inch. We have come to the decision that we have a gremlin in our pool. How can a pool leak so much water and you can't find where from and then overnight stop leaking. Please help me with anysuggestions you may have as we are all at a loss and don't want to fill in the garden to have to dig it up again.  
 
Thank you 
 
Charmaine

Charmaine,  
 
 
 
Yeah, I've encountered several pool gremlins myself:)  
 
Question: Was the pool pump running both when you lost water and when you did not? If the pump was running when you lost water but not running when you didn't it sounds like you could have a leak on the pressure (discharge) side of your plumbing. Water is sucked in through the front of the pump and discharged out of the top. If you have a leak on the discharge side you will loose water quickly when the pump is running as a result of the pressure on the line, but loose little or no water when the pump is off. The reason the water level may have stabilized at the bottom of the skimmer may be because the pump began to draw air when the water level became too low and lost prime. 
 
 
 
Conversely, if the pump was not running when you lost water and running when the water level remained stable then the leak could be in the skimmer line. This is the case because when the pump is running a suction line leak will not loose as much water (typically) because the suction from the pump draws air into the line, but when the pump is off the line if free to leak. If the leak is in the skimmer line the water level would have naturally held at the bottom of the skimmer. In this case, if the pump was running when your pool guy was searching for the leak he would not have seen it because it does not leak with the pump running. If you do indeed have air bubbles returning into your pool then there's a 99% chance it's in the skimmer line. 
 
 
 
Question: Do you have any water features or other plumbed features of the pool that were running at the time of water loss, but not running when the water stabilized? If so that's an indicator that there may be a problem there. 
 
 
 
Here's what needs to happen Charmaine: Someone needs to pressure test your entire plumbing system if they have not done so already. If no leak turns up there the pool needs to be checked for a structural leak (dye test). Between these two tests the leak should turn up. If the leak is structural (probably not the case) then the repair is straight forward. If the leak is in your plumbing, the pressure test will indicate which line is leaking, but not necessarily where it's leaking. Your pool guy can try to find it the hard way or there are companies that can pinpoint the leak within 6" even under ground or under concrete (hopefully not) with precision equipment. Try to be patient with you pool guy though; unfortunately these things happen to the best of us. Let me know if there's anything else I can do to help. 
 
 
 
Take care and good luck, Jason