Leak found...How should I fix it?

bluenoise

LifeTime Supporter
Jul 25, 2007
187
Alamo, CA
I had American Leak Detection out to my house this morning. I really like these guys. The local office has been great to work with over the past few weeks of me bugging them with questions and the technician that came out this morning was on-time, courteous, and thorough.

He spent about two hours checking everything on my pool. Overall, it's good news. None of the plumbing leaks at all and the pool is, for the most part, structurally sound. It does need new plaster, but we already knew that. He found a leak in the skimmer throat where the plastic is supposed to butt up to the plaster. There is a gap there about 1/16" wide and it's drawing water. He used a syringe with a florescent dye and showed me how the dye got sucked into the crack. He didn't measure the loss rate, but he said it was completely reasonable for that leak to drop the pool >1/2" a day. The fix is pretty simple as there is no digging and no cutting of concrete. I'm going to look into fixing it myself first, but he quoted me $450 for a permanent fix using "polymer grout" that gets injected in behind the skimmer's plastic. That seems a little steep, so I'm going to see what I can find about the process and product used. It shouldn't be that big of a deal. The other option he presented was to use pool putty epoxy and jam it into the crack, but he said there's no guarantee on that holding up and it is a temporary fix at best.

Hopefully, that is all that is wrong and we can be done with the heavy water usage and the loss of salt level (due to refilling with fresh water every day).

Does anyone know anything about the polymer grout? He says it's much like the expanding foam product "Great Stuff," but it doesn't get rigid when cured. It stays flexible so it can adapt to any earth movement, etc. He showed me how it is hollow beneath the area of the leak, so they'd drill a small hole in the plastic throat of the skimmer, squirt in the polymer grout, and then wait an hour for it to cure. Then, they'd clean off any that oozed out and finish it all off with some epoxy putty to make the plaster-to-plastic transition look nice. He says that last step is completely optional as it doesn't do anything for the leak. It's just cosmetic.
 

bluenoise

LifeTime Supporter
Jul 25, 2007
187
Alamo, CA
That's exactly the product the guy used to plug the conduit on my light niche "just in case it springs a leak." He says it's great stuff for many things, but he didn't think it would make a good permanent repair in this situation since it doesn't flex. I'm all for giving it a try, though, if I get convinced it's going to last.

Thank you for the link. I bookmarked it as I may be ordering it.
 

bluenoise

LifeTime Supporter
Jul 25, 2007
187
Alamo, CA
Well, I fixed the leak found by the LD guy and confirmed it is fixed by dripping some colored water near it. I used the pool putty and it did a nice job.

However, I'm still losing water, albeit much more slowly. I've been conducting bucket tests all week and finding my pool is going down almost twice as quickly as the bucket's level. I filled the bucket to about an inch from the top and set it on my top step, which is about seven inches deep. The bucket loses about 1/8" per day while the pool loses 1/4".

I don't know where else to look. The LD guy seemed very thorough. He even sealed up the conduit for the light "just in case." All the plumbing held 25 psi for 15 minutes, so it's not the pipes. There are no visible cracks. Any dye deposited near the returns just sits there without any draw.

Does anyone have any suggestion as to where else to look?
 

bluenoise

LifeTime Supporter
Jul 25, 2007
187
Alamo, CA
I called the LD folks and they were very understanding. As I talked to the gal on the phone, I explained what we're observing and asked I do the bucket test one more time just to be sure it's still leaking before she sends someone out again. I did it last night and both the bucket and the pool dropped about 1/8" overnight. So, no leak, it would seem.

As my wife and I looked at it, though, a new theory as to why it's intermittent emerged. We like to keep the level pretty high and that level is usually even with the pool fill inlet. When it's that high, the pool seems to leak, but not when it's lower. Right now, the level is about 1.5" below the inlet. So, the guess is it's leaking back out through the fill inlet. That's the only thing the LD guy didn't test as that's above the normal fill level by about 2". I'll try keeping the level below that for several days and observe the rate of loss with repeated bucket tests. I'll also use some pool putty on the inlet opening, since I have some anyway.
 

carlos31

Well-known member
Oct 18, 2007
104
Central Texas
pressure testing

I am not a plumber so take all of this with a grain of salt but...

I decided that I should test my plumbing (installed it myself) before the decking is poured; especially after seeing the 7000 pound Bobcat compacting the roadbase which is over the sand filled plumbing trench. So far I have tested all my wall return lines, floor return lines, and main drain but not the skimmers or waterfall lines.

I have found test guidelines on the internet ranging from 20psi/15 minutes up to 45psi/30 minutes. For the return lines I have been testing at 40psi/30 minutes. All was well until the final floor return dropped from 40psi down to 20 psi then held. I left it at 20psi overnight and it just sits there. I repeated this a few times always with the same result. Not to highjack your thread but if anyone thinks this merits a fix versus leaving it , please advise. I am leaning towards leaving it alone since I don't think any of my returns will ever get close to 20psi. But I am not sure what the norms are for psi in pool plumbing.

While doing this I have been creating simulated leaks by using the relief valve on the pressure tester. I was surpised how I could create a minor leak without the pressure gauge dropping when testing to lower psi levels like 20psi. In short, based on what I have seen I don't think 25 psi/15 minutes is enough to detect a small leak in a pipe. IMHO, the test has to be higher pressure or a longer test time.

I realize that higher pressure may be a problem when using the closed end test plugs. No matter how hard I cranked mine shut, I was able to blow them out at around 40-45 psi. So instead I just cemented caps on my lines but this is not an option for a finished pool.

Also, take a look at the tester's pressure gauge if he runs another series of tests. I would be more inclined to trust the test if his gauge ranges from 0 to 30 psi. If its a 0 to 200 or a 0 to 300 gauge then I doubt the small drop in pressure associated with a small leak would be noticeable in just 15 minutes.