Pool losing water

[Cainel]

I've been losing water in my pool for several weeks now. It happens only when the pool is on. It will drop 1.5-2" in a normal filter cycle. I don't have any visible leaks at the pool equipment and no bubbles in the pool. If the pool is not running for a full day the level does not drop. Are there any quick things I should check myself before calling a leak detection company? someone suggested it might be my backwash valve....but they weren't looking at my pool and I'm not sure what to check for there...

any advice is appreciated

 

[Texas Splash]

Water loss only when the system is running would seem to indicate a problem on the pressure side - after the pump from the pump/filter back to the pool return jets. I would inspect very closely around the pool for any soft spots that may indicate water seeping from underground. As for the equipment pad, if you don't see any active dripping, check your filter's multiport valve - assuming the DEL48 has a MPV. If equipped, the MPV may be leaking to waste without you knowing it. Check the filter's waste line for any water loss which could indicate a bad MPV internal (spider) gasket or other defective part/seal.

 

[Cainel]

Our pool is surrounded by gravel and pool decking so I'm having a hard time finding any soft spots, plus we have had a ton of rain the last few months in DFW.

Is this the filter waste line I should be checking? There is no water running through it when the pool is running.

 

[Texas Splash]

Is this the filter waste line I should be checking? There is no water running through it when the pool is running.

Sorry, another reminder I'm not getting any younger. I can't see that image well enough. But if that line is coming off from the multiport (or plunger) valve and going out to the yard or into a drain, it's your waste line. Since no water is flowing through it, you should be okay there.

 

[Cainel]

I was hoping that WAS the problem. Any other suggestions on where to check? If not, going to hire someone.....

 

[Texas Splash]

Any other suggestions on where to check? If not, going to hire someone.....

Based on your scenario, I'm afraid not. The pressure side (from filter to each return jet) may need to be pressure tested or with other means (i.e. sonar, ultrasound, etc). The good thing about those high-tech methods is they can often times find a leak within inches which helps to avoid unnecessary digging. Hope things work out. Let us know how it goes.