Identifying big leak

[poolboyp]

My pool has a 4 ft retaining wall. It has been losing a lot of water per day the last few days like probably 3" per day and it's been cooler than the summer when we would lose maybe .5" a day.

Today I went in the opposite side of the retaining wall and there is standing water.

I tried the pool dye technique to check all of the jets. The only ones that look suspect are two of the hot tub returns and when firing the spa up alone there was noticable air bubbles coming from those returns only.

The next thing I checked was the suction side. I have two skimmers and the double main drain piped together, and well as the hot tub main drains. I was able to run the pump fine off both skimmers alone but there is a considerable amount of air, like a LOT when I turn only the main drain valve on on the suction side.

About three hours after shutting off the system the hot tub was down probably 4" and I noticed the backflow preventer for the spa noticable was half way full of air on the return.

I was thinking to leave the system off for 24 hrs to try to isolate if it is one big leak or two leaks. I have a feeling though if the hot tub return pipes are leaking they would only drain down to about the top of the return line, right?

I was considering shutting off the spa valves and running the pool again tomorrow if the pool level has not gone down and then if both continue to drain, I was considering to swim down and plug the main drains with the rubber plugs. This is not going to be easy though as the water level is about 8ft.

One other odd thing I noticed is that when I put the pool in to service mode that on the return side the jandy valve does not completely shut off the Spa returns (the fountain returns are separate). Is it normal for a small amount of water to go to the spa still? The problem is there is no manual valve to shut off the spa returns, only the fountains, so unless I adjust the valve stops i can't run the pool cimpletely isolated from the spa.


Sorry for all of the questions at once!

 

[JJ_Tex]

You have a lot going on, but think you are on the right track in isolating the variables until you find the culprit. Start with the items closest to where you see the standing water. Also read up in the pool school on leak detection:

Leak Detection

A number of things can cause leaks in your pool. You can learn tricks for leak detection and how to pinpoint where your pool is losing water.

www.troublefreepool.com

 

[Bperry]

Try turning off the system and put a plug on every return jet and the skimmers to see if that stops the water loss. If it does, remove the plugs one by one waiting a bit to see if the water level starts dripping again. If it does, you found the line with the leak.

The only thing that doesn’t find is a main drain, light fixture, or a shell leak.

 

[Bill1974]

Does it seem like more water is lost when the pump is running or when the pump is off. If running it's more likely on the return lines. On or off then it's likely not a line. If you see bubbles in the returns the suction slide is more likely where it is. If there is less water loss when running it also points to the suction side.

With a 3" per day loss it should be pretty easy to narrow it down. Like others have suggested closing and isolating lines should narrow it down.

There is also the option of hiring a leak detection service.

Has anything changed recently around the pool, any work done around it?

If you can plug all the pool side connections you may able to pressure test each line to see which one does not hold. Even with plugs that don't seal perfectly you should be able to see which one leaks down the quickest.

 

[poolboyp]

Does it seem like more water is lost when the pump is running or when the pump is off. If running it's more likely on the return lines. On or off then it's likely not a line. If you see bubbles in the returns the suction slide is more likely where it is. If there is less water loss when running it also points to the suction side.

With a 3" per day loss it should be pretty easy to narrow it down. Like others have suggested closing and isolating lines should narrow it down.

There is also the option of hiring a leak detection service.

Has anything changed recently around the pool, any work done around it?

If you can plug all the pool side connections you may able to pressure test each line to see which one does not hold. Even with plugs that don't seal perfectly you should be able to see which one leaks down the quickest.

Well we didn't have rain for months and then we did and presumably the ground settled. That is only thing I can think of.

Good news I was able to determine it is 100% the hot tub returns I drained to the spa down to a few inches above them yesterday and today 0 water has escaped the pool but the spa dropped down to the return lines quickly and then stopped.

I don't know why there is air in the main drain but I was thinking it's very possible they are mostly plugged or something already before I purchased the home.

I bought 1.5" plugs and am plugging them in the pool for now but the jandy valve is not fully closing off that side. I was thinking it's possible is this part of freeze protection to make sure water is always flowing on that side.

For now I'm going to watch a video or something on how to adjust the stops in the jandy valve so I can get circulation again and make sure these are the only leaks.

I'm assuming this is going to be a major repair so everyone pray for me lol

 

[poolboyp]

Oh and any advice for emptying the line before plugging would be appreciated so as not to break anything else in the winter that is soon to be here

 

[Bperry]

Oh and any advice for emptying the line before plugging would be appreciated so as not to break anything else in the winter that is soon to be here

Generally blowing air in the line with a cyclone blower (some can get away with a shop vac) will push the water out and then you can cap it to airlock any vertical runs.

 

[poolboyp]

Generally blowing air in the line with a cyclone blower (some can get away with a shop vac) will push the water out and then you can cap it to airlock any vertical runs.

Nice thanks. I have an air compressor and a shop vac. I guess it doesn't have to be 100% dry just mostly empty to allow for expansion during freezing?

 

[poolboyp]

Jandy valve stop adjusted, plugged the jets for the spa, and am running the pool pump again. Definitely not leaking like before.

I'm probably going to leave the valve for the main drain shut off for 24 hours to monitor the level without it and then open it and check it there was any difference in water loss.

Thanks for the help everyone!

 

[Bill1974]

An air compressor (at least what people commonly have at home) don't move enough volume of air to do an good job, plus there is a risk of over pressurizing the lines if you don't regulate the pressure down to a pressure that is not going to damage anything. I use the exhaust from a shop vac (it's a large Ridgid shop vac), I will let it a few minutes on each line before capping each line. Cap/plug the line while it's being blown out. Expect to get a little wet.