Looking for that leak in ...

[mcleod]

the pool decided to leak as we started the opening. I've been with @Dirk's help and have been working on isolating the leak if possible. The pool is about 9 inches below normal. It is below the skimmer boxes. The returns are still underwater as are the two main drains, which are isolated at the pump, which has been off for the duration of this search. The water level loss from last night to now is a "fat" inch or so; about the same as it was yesterday.

To determine if there is a leak at the fittings I'm going to attempt the dye test. I'm going to use a squeeze bottle with a small diameter nozzle, I hope for accuracy. The questions. 1) Use the food cloring full strength or dilute with a bit of water? 2) If the dye reveals a leak at the fitting, what would be the best way to seal that fitting to the vinyl? 3) Any hints for dye testing the vinyl verticals?

McLeod

@Newdude @Texas Splash @mknauss

 

[Texas Splash]

I never diluted the dye when I squirted it in. It will dissipate on its own. If you find a cracked fitting, repair might depend on the severity of the crack and/or exact position in the fitting. If you find a defect let us know and we'll do some brainstorming. As for the vinyl verticals, I'm not 100% sure. If water was pulling through those, I would think the dye would be seen going in.

Just to be safe, I suspect you've already ensured there is no water draining out the waste pipe unintentionally correct?

 

[Dirk]

Just to be safe, I suspect you've already ensured there is no water draining out the waste pipe unintentionally correct?

You mean from his filter? Dern it, I didn't think of that! We've been analyzing how the water drops and what's been going on in his yard (some recent work was a suspect). He's been monitoring the bucket test the whole time, so he ruled out evaporation. He just replumbed his pad, and had his filter disconnected for many days during that work, so that waste line might be a contender. Thx Pat.

Edit: strike that. He's had his main pump off this whole time. I have him circulating FC with a sump pump. So it wouldn't be the waste line with the pump off, right?

 

[mcleod]

OMG! This is getting as exciting as a Tom Clancy novel! Everything has been off for more than a week. But I'm going out to check. @Dirk @Texas Splash

 

[Newdude]

So it wouldn't be the waste line with the pump off, right?

If it's in recirculate it can siphon drain by gravity alone.

Get pics of the returns when you can. Plug them if possible.

 

[mcleod]

@Dirk, @Texas Splash confirmed no filter leaks. Have just taken a syringe with red dye and squirted the returns and the vacuum pressure outlet. There seem to be no leaks around the gasket fitting on the poolside of the vinyl. that leaves the main drains or the vinyl. How to proceed from here?

McLeod

 

[Texas Splash]

A follow up to the jets, just be sure there are no cracks inside the jet fitting. I had one last year in the 12 O'Clock position and had to replace the entire jet fitting.

 

[mcleod]

@Newdude @Texas Splash @Dirk
these pics were just taken. Red dye stays close to return outlets except in one place where a trail of red stretches about five feet from the outlet. Water is still. this trail of dye is out a bit from the vinyl. I saw no dye being drawn to the vinyl.
View attachment 573231

 

[Texas Splash]

I would guess the next areas to check would be the drains and the liner. You would hope the water will stop dropping soon to indicate a waterline area with a puncture, but you never know until it drops.

 

[Newdude]

The stair trim is a common spot also.

This would be my excuse to buy a Mini scuba tank so i could easily plug the main drains for comparison.

 

[Dirk]

Which port is this? Has the water level ever drained down below it? Or has it stopped here? It looks to be under a lot of stress. It's poking out, and there's a big wrinkle just below it. It's definitely been tweaked out of its original position.

Sidebar: you don't need to keep addressing any of us. Now that we're a part of this thread, we all get alerted whenever anyone adds to it.

 

[Dirk]

On second look, they all look tweaked out of position. I say let it leak, to see if the water drains down below the returns.

 

[Dirk]

As I've been talking through this troubleshooting with @mcleod, the factor that is well outside of my wheelhouse is the stress to the pool structure. I wouldn't even want to drain my concrete pool like this. How much draining can a vinyl pool withstand? We're already seeing sags and wrinkles. Can the vinyl take this torquing? Is there a possibility the structure behind the vinyl will give way? How deep can he safely go? Is he already past that point?

 

[Newdude]

How much draining can a vinyl pool withstand

It needs 18 inches of water in the shallow end to hold the liner in place. Sometimes 12 is enough but if going that far it needs to be babysat in case it starts shifting between 18 and 12.

We're already seeing sags and wrinkles

That may be entirely unrelated. IMO a current leak wouldn't have made those wrinkles, it'd be making large water bubbles that would turn into wrinkles when they finally absorbed into the ground.

The liner appears past its prime either way.

Is there a possibility the structure behind the vinyl will give way?

If it drained the shallow end dry and a big storm hit, the saturated ground might overpower an equally aged steel wall. Or not. They're pretty tough for a couple decades. Half full in the shallow end is probably enough 'push back' to hold no matter what.

 

[mcleod]

The stair trim is a common spot also.

This would be my excuse to buy a Mini scuba tank so i could easily plug the main drains for comparison.

Alas! I've given or sold most of my SCUBA gear including my pony bottle. Still have regs, wet suits, etc. The pool is shallow at deep end-less than 5 feet

 

[mcleod]

View attachment 573264

Which port is this? Has the water level ever drained down below it? Or has it stopped here? It looks to be under a lot of stress. It's poking out, and there's a big wrinkle just below it. It's definitely been tweaked out of its original position.

Sidebar: you don't need to keep addressing any of us. Now that we're a part of this thread, we all get alerted whenever anyone adds to it.

Morning one and all
The pool is down about another 1/2 inch. Less than yesterday. The port in question is the vacuum port. This morning's exercise will be to see if I can remove the main drain covers and plug the mains (depth is less than 5ft), refill the pool a half inch higher (yesterday's mark), and see what happens. Alternately I am considering exploring the water line, an inch above and an inch below to check the vinyl. The pool came with the house and we have no info as to the age of the pool installation. Yes, the vinyl is likely in need of replacing but would like to postpone that a while longer, if possible. Thoughts on whether the course of action should be to plug the drains and wait another 24 hours, or explore the vinyl?

Is it necessary to remove the drain covers for doing the dye testing?

 

[Newdude]

Yes, the vinyl is likely in need of replacing but would like to postpone that a while longer, if possible

Trust me. We get it. None of us wants to be out $8500 today.

 

[Dirk]

Is it necessary to remove the drain covers for doing the dye testing?

I would think so. If one of the drains is leaking, and you could get the dye to suck into one of them, with the covers in place you wouldn't be able to determine exactly what is leaking. And if you couldn't see the dye get sucked in with the covers on, you wouldn't really know if one of the drains was leaking, or if your dye just didn't get close enough to the leak.

Shallow water blackout is a thing. It's just what it sounds like: blacking out under water from holding your breath. DO NOT mess with your drains unsupervised. Have someone that is capable of retrieving you, and ideally resuscitating you, standing by while you work underwater. NEVER WORK ALONE UNDERWATER IF YOU HAVE TO HOLD YOUR BREATH FOR EXTENDED PERIODS!

 

[Dirk]

Thoughts on whether the course of action should be to plug the drains and wait another 24 hours, or explore the vinyl?

You haven't let the water drain down far enough to determine if it is a return or not. And based on the pics, if it's that vac port or not. If it drains down below all the returns, that means it's not the returns. If it stops at the returns, then it's one of them. Remember, the plugs you have in your returns only eliminate the return piping for now, not the return fittings themselves.

Have you "officially" seen the water drain below the vac port, and keep going? That would eliminate the vac port, but if not, then that is still a contender.

If by plugging the drains the leak stops, yes, that will determine something. But if that doesn't stop the leak, you'll still have to let the pool drain below the returns. So it's a matter of in which order you test. Since the water level is so close to the returns now, and not really below that vac port yet, I would test those first before I jumped in and messed with the drains.

The advantage to testing the drains now, is that if it is the drains, then you don't need to lower the water below the returns and so save compromising the pool structure any more than you have to. (You may have to drain the entire pool at some point, to fix the drain leak, but not until you're ready to.)

So it's up to you in which order of things you test.

 

[mcleod]

Morning all
As of this morning, the pool has dropped another 7/8ths of an inch. A little slower than the 24 hours prior. Return #1 which is at the higher end of the pool (meaning that my pool is not level end-to-end) is about 1/3 exposed now; the others are still underwater. I may venture into the pool to dye test the light later today, and perhaps the returns again. I've got about 8" to go before I hit the critical 18" water depth in the shallow end. I've culled leak detection companies. Do I make the call before the pool gets much lower?

McLeod