Air bubbles and water loss

[phlach]

Hi All,

19k gal inground pool. I definitely have a leak. Bucket test shows water lose due to the leak being at about 1 1/4 inches per day. Around the same time I noticed I was topping the pool off more often, I noticed air in my return jets. I've narrowed it down to the main drain suction line (when I close the valve coming from the main drain, the bubbles go away. I fear a dug up back yard and costly repair is in my near future. I'm assuming, but perhaps I shouldn't, that the problems are related? Any advice before I call my pool guy?

Thanks in advance,
Ron

 

[duraleigh]

I would not assume they are related. I would find the water leak first. The simplest first attempt is to let the water leak down until it stops and then assume your water leak is at that level. Have you done that?

 

[phlach]

Thanks, I'll give that a whirl. I've been running the pump 24/7 to clear up cloudy water (opened to a green swamp this year). Perhaps running a bucket test with the pump running vs not running would also be helpful. I'm curious to see if I see the same water loss with the pump running vs not running. When I opened the pool, the water was all the way up to the overflow opening coming off the skimmer, so I assumed the problem probably wasn't in the liner, but you know what they say when you assume. I'll run some more tests and report back.

 

[jmhjgh]

Who winterized the pool last year? If you pay someone, you should be calling them if you suspect a main drain leak. Also, if it is the main drain, I would consider plugging it off before I would break up a pool deck for repair.

 

[phlach]

Thank you all. I first noticed the water loss toward the end of the 2012 season. Pool was closed all of 2013 because I had medical issues. Pool is open again now for 2014 (yay, but now I get to deal with the water loss issue I first noticed in late 2012). Here are some test results.

All tests involved the "bucket" test so that I could remove evaporation from the equation.

Test 1: Pump on, all valves open, daily water loss due to leak 1.5"
Test 2: Pump on, skimmer line closed (only drawing water from the main drain), daily water loss due to leak 1.5"
Test 3: Pump OFF, all valves open, daily water loss due to leak ZERO.

So, I think at this point I've ruled out a leak in the liner. And I've inspected everything plumbing related that is above ground from top to bottom. I'm suspecting one of the two main return lines under ground.

We have a third return line that was put in for an eventual water feature. I just ran some pvc from that into the pool, and have turned off the regular return lines to the pool. I'm thinking that if water levels holds, I've narrowed it down to one of the two regular return lines. I also notice a little sand or dirt near the return jet in the shallow end. I'm suspecting that line may be the culprit. I inspected my sand filter top to bottom, laterals look perfect. Unfortunately I don't have individual return line valves to test each of the two regular return lines separately. If water levels hold with all water returning to the pool via the water feature line, perhaps installing a directional valve for the two main lines would be the next step. Any thoughts? Thanks again to everyone who has taken the time to respond. Much appreciated!