Leak in return? [new here, help please]

[roomruler]

Hi guys,

This is Max from Winnipeg, MB, Canada.

I bought a house with an in ground pool 2 years ago and this is my second season. Since I replaced the liner and solar cover this year, I paid a lot of attention to the pool water level after the project.

I noticed the water level drops quite a lot even with cover on (refer to my avatar pic). 1/4 inch for 9:00 pm to 9:00 am and another 1/8 inch for 9:00 am to 9:00 pm.
By the way, the heater is broken but water is quite warm thanks to the solar cover.

I think this would be too much for a covered pool due to evaporation so I did the dye test.

I have 2 returns in my pool. I found one return sucked dye into the opening. It seems to be quite minor since I need to apply the dye really close to the jet to see it to be sucked in. But by comparing 2 returns, there is indeed a difference.

Now I am really panic about the underground pipe leaking, thinking about digging a hose in concrete deck just terrifies me!!

I am going to do more test to confirm the leak. The first idea is that, if it’s return underground pipe which is pressure side, turn off the pump should reduce the leak a lot. I post this thread mainly to comfort myself by joining a big community.

Any suggestions appreciated! And the dye test really accurate? I mean, is there a possibility my dye test is wrong?

 

[ajw22]

Welcome to TFP.

Pics of your pool and the suspected leaking return to see the construction of it would help.

Could the leak be from the liner junction with the return and not the return piping?

 

[jimmythegreek]

How big is the pool gallons wise? Quarter of an inch in dryer weather is normal but with a cover and humidity it may have a small leak. Any chance your valves let you turn off individual returns?

 

[ship of fools]

I've been able to dig under my concrete deck to repair a collapsed skimmer line - granted I was upside down in a hole and it wasn't too enjoyable but it was better than the alternative!

 

[roomruler]

Welcome to TFP.

Pics of your pool and the suspected leaking return to see the construction of it would help.

Could the leak be from the liner junction with the return and not the return piping?

Thanks for your reply!
I’ve attached the pics of my pool as well as the suspected return.

Pool is around 15-20 years old, I am not the original owner. In general, it’s in a good shape. This year is my second season and I determined to maintain it well. A plumber, who also builds pool, helped me replace the liner around 2 weeks ago.

For that return, during the liner replacement 2 weeks ago, i was told one of the 4 screws on the faceplate was stripped, likely from longtime ago since the bottom of old screw rust. The plumber put silicon and then send the screw in. I was told it should be fine or he will do further repair when I close the pool this year, by drilling additional screws into the steel on either sides. This is the reason i suspect this return at first place. However, the dye tests around the screws, as well as the fitting between faceplate and liner, turned out to be fine. The dye was sucked into the opening slowly (not quite obvious, but different from the other return). So I am suspecting the pipe.

* The return pic is not quite clear because it’s raining so hard tonight

 

[roomruler]

How big is the pool gallons wise? Quarter of an inch in dryer weather is normal but with a cover and humidity it may have a small leak. Any chance your valves let you turn off individual returns?

Thanks for your reply!

My pool is rectangle 15 ft by 36 ft, around 22k gallon.

Now I calm down and think about it. I thought pool cover should make the evaporation quite minimal. However, I lost 2/8 inch at night and 1/8 inch in the day. We had cold night when i did the measurement, so it could evaporate more at night. Since I run the pump all the time, the leak should be the same. Even I count the 1/8 inch daytime entirely to leak, I still got 1/8 inch for evaporation at night even with cover on. That makes me think there should be still some evaluation daytime and the leak should be much less then 1/8 inch per 12h. So the leak maybe quite small and likely has been there for a while.

There is no valve allowing me to shut off one return. I plan to see how water drops if I turn off the pump, that should definitely make a difference if I got pressure side leak.

It’s hard to believe, when I think my pool leaks, it just keep raining...

 

[ajw22]

It may look like the dye is getting sucked into the pipe but everything you describe points to the return fitting. It would be too much of a coincidence for the pipe to break just as you worked on the liner.

 

[roomruler]

I've been able to dig under my concrete deck to repair a collapsed skimmer line - granted I was upside down in a hole and it wasn't too enjoyable but it was better than the alternative!

Thanks for sharing your experience. I can imagine definitely not enjoyable. I don’t feel confident to do that kind of job myself. My plumber/pool builder told me, if there is indeed a leak in return pipe, it’s likely in the joint right behind the pool wall and the job of digging concrete and fix probably will cost me 1200 cad. I am preparing for the worst and trying to do more tests to confirm the leak first.

I find the key is to calm down to deal these pool issues.

 

[roomruler]

It may look like the dye is getting sucked into the pipe but everything you describe points to the return fitting. It would be too much of a coincidence for the pipe to break just as you worked on the liner.

I will try the dye test again to confirm this. Maybe the minor leak (as I explained in the above reply) has been there for a while. I didn’t pay that much attention to water level last year.

 

[ajw22]

I think you have to take a closer look at the liner and return fitting before you start digging.

 

[roomruler]

I think you have to take a closer look at the liner and return fitting before you start digging.

Thanks, will keep that in mind.

 

[roomruler]

Just an update here. In order to have a close look at liner return fitting, I bought a proper dye test syringe from pool store. Also, this time I took off the eyeball from my return jet to better access liner/fitting part. However, this time I didn’t see the dye being sucked anywhere. I mean the move of dye just so slow and the test is inconlusive.

I remove the solar cover and start to doing bucket test. I’ll post my further update here.

Thanks!

 

[MApool25]

Hi, I read your question and it sounds similar to mine. Do you know if flex tube was used for your lines underground. I found out recently that mine are flex and that termites have gotten to them and I leak a significant amount through my lines. I assumed, like many people, that termites do not go after plastics, etc, but they will if they are in their way or if they sense water. I'm in process of replacing my lines because of this. I heard in Canada flex pipe is commonly used.

 

[ajw22]

Termites Damage Pools Inground, Above Ground or Pipes

Pool Liners and Pipes can be damaged by Termites

poolpatcher.com

 

[roomruler]

The bucket test shows my pool should be fine.
It seems that, sometimes, the solar cover can make the water quite hot and in fact leads to more evaporation at night (if night was quite cold)

 

[roomruler]

Hi, I read your question and it sounds similar to mine. Do you know if flex tube was used for your lines underground. I found out recently that mine are flex and that termites have gotten to them and I leak a significant amount through my lines. I assumed, like many people, that termites do not go after plastics, etc, but they will if they are in their way or if they sense water. I'm in process of replacing my lines because of this. I heard in Canada flex pipe is commonly used.

Thanks for your reply. I’m not quite sure about the flex pipes. I remembered the guy who replaced the liner said, the underground pipe should be rigid and if there is an issue of underground pipe, likely to be the joint right behind the wall or the T near the equipment pad joining pipes. But he cannot assure anything since he didn’t build my pool.

My pool seems to be fine after bucket tests. I’ll keep an eye on it.

I’m in Winnipeg, Manitoba. The pool is directly exposed to sun 6:00 am to 9:30 pm. And the night can be cold.

 

[roomruler]

[update] in case anyone has the same situation and finds this post, my pool was leaking. It got worse last year (2020) and I asked a professional for help. Both returns were leaking from the joints inside.