Possible leak

[H-12 1/2 Mike]

My pool is a 16,400 gal gunite which is 20 years old. Recently I have noticed a loss of water of about 1" per day. I have checked all of the obvious areas for leaks but have detected none. I had the pool checked for cracks and none were found. I guess the next step will be to check the underground plumbing. Any ideas on how that is accomplished?

 

[ping]

What are the obvious areas that you have checked? Have you checked all the valves, maybe a check valve gasket that leads to a waste line that will not show a leak due to it going to waste.

 

[Divin Dave]

The title is your thread is "Possible" leak. Are you absolutely sure you have a leak? We have had some really nice weather lately here in TX with a bit of breeze which will accelerate the evaporation. Have you done the bucket test? Heres how.
https://www.youtube.com/watch?v=U36G-LVproY

The easiest way to test the underground plumbing is to put "stoppers" in all of the plumbing lines.
Each return, the skimmer, any pump lines you have, etc.... and then let the pool sit to see if there is any water loss.

With all of the lines plugged, if there is still water loss, then I would look at the conduit fitting on the back of the light fixture.
Maybe around the perimeter of the skimmer? Leak finder dye helps find things like that. Maybe an interior corner of the skimmer.

For plumping test....With the lines plugged and there is no water loss, then remove the first stopper nearest the waterline and let it sit to see if there is water loss. If not, remove the next stopper nearest the waterline and let it sit. continue removing stoppers until you find the culprit.

Of course there is the option that you leave all of the lines unplugged, turn off the pump and let the water level continue to drop. When the water has stopped dropping, you have found the leak.

 

[H-12 1/2 Mike]

Thanks for the bucket test idea. I will give it a go after the rains have passed through. Then I will move to the next step if needed. Yes, the winds have been good all week with warm temps (great sailing).

 

[JonnyB]

Other then the bucket test the easiest way to see if its a leak is to stop putting water into the pool. After the rain stops take measurements from the coping or tile line (do this always at the same time of day). Try changing your pump run times to see if that changes the amount of water loss.

 

[H-12 1/2 Mike]

I have just completed the bucket test and have confirmed that we are losing 2.25" of water during a 24 hour period. The only abnormality was that the freeze protection was activated last night which allowed the pool to run for 24 hours. I guess the next step is to track down the leak. Is it worth paying $500 to have the pool company do that troubleshooting?

 

[JonnyB]

Do you have a valve that can shut the skimmers off? Try turning them off and running the pool with the bucket test. I personally was loosing 2" a day when BOTH of my pool lights were leaking. the fun part with my leak was that it depended on the temperature of the water. Once it got to 59 or lower it started to leak. After further investigation I realized the expansion joint wasn't done properly and when it got cold the concrete moved.

 

[H-12 1/2 Mike]

I also noticed my leak with the colder water temps. Did
not loose this much water during the summer and fall.

 

[H-12 1/2 Mike]

The skimmer and main drain are in one pump inlet. So I assume it is not practical to run one without the other.

 

[JonnyB]

if you haven't already I would try doing a dye test with the skimmer while pump is on and off.

- - - Updated - - -

I just saw in another post you have a spa spillover. Any fountains or waterfalls will increase evaporation that will throw off your bucket test. BUT with that much water loss you still have a leak

 

[H-12 1/2 Mike]

Pool still losing 2.25" per 24 hrs. This time the circulation was not running. I will let the pool set idle until the loss of water stops so I can determine which area the loss is occurring.

 

[H-12 1/2 Mike]

Lost another 1.75" during the last 24 hours. The level is now at the bottom of the skimmer so if there is another loss it will not be because of the skimmer.

 

[Divin Dave]

my money says its the conduit on the back of the light niche.

 

[H-12 1/2 Mike]

Just took another measurement and the water level only dropped 1/2" over night. The water level is now well below skimmer level but the loss of water has been reduced from 630 gals per day to 142 gals per day. I have arranged for Texas Leak Protection to come out next Wednesday to help identify all of the leaks. I know the skimmer area is leaking but where are the others? Should I go ahead and add water to the pool now in order to be able to filter and add chemicals?

 

[H-12 1/2 Mike]

Just took a measurement and the loss of water is now 1/4" which is 71 gals per day. It looks like the skimmer area is the culprit.

 

[H-12 1/2 Mike]

Applied pool putty - Expoxy Bond to the perimeter of the skimmer. I am skeptical as to whether this will work, the putty seemed too thick to really get down into the cracks. If it does not, tomorrow I will replace it with the marine 3M 5200 that I use for underwater fittings on my boat.

 

[JonnyB]

good to hear it might be the skimmers. I have tried using 5200 with the pool but its a mess to deal with. The stringy mess in the water then getting on plaster ugh don't want to do that again.

 

[H-12 1/2 Mike]

What do you use?

 

[H-12 1/2 Mike]

Only lost 71 gals overnight after sealing the skimmer with putty. It appears the leak has been stopped but I will continue to monitor the water level for another week.

 

[ping]

If you have a cover, put it on to eliminate evaporation being in the equation of how much is being lost to evaporation. You can also do a bucket test again.