Pulling out my hair with a pool leak!!!

[phild]

Hi,

perhaps someone can give me some advice and or help regarding the leak in my pool.


First some information about my pool and if I haven't covered everything, please ask.

location is Saint Louis Missouri (evap chart says .25 to .5 inch drop per day)
in ground pool
built in the late 70's (we've been in this house for 5 years)
about 20K gallons
strange construction... concrete bottom and fiberglass panels for the sides.
concrete skirt (pool deck) around the pool for 6-8 feet, then grass
equipment is about 30 feet away.
equipment is downhill, below level of water, but not below the bottom of the pool.
SWG System
main drain
2 skimmers
4 return jets
pump is set to run 24 hours.
2 lights

About 2 years/18 months ago, we had the pool deck redone and at that time had all of the plumbing replaced, the lights and light shells replaced, an extra skimmer added and the pool equipment moved out of the way. The pool equipment (pump, DE System, multi valve, SWG and power) was all new as of the previous year.

We also had the pool painted.

The guys that did the work, appeared to have trouble with a leak which they worked at for a while and I believe fixed by putting putty around the light(s).

Last year, summer of 2009, we thought the leak was back, so this year when I opened the pool, I drained it down to where the shallow end was completely dry. I then carefully went around and sealed all the panel seams with 3M 5200, also around the light shells, and the skimmer frames on the inside of the pool. I felt very confident (and still do) that if there was a leak around any of those areas it should be gone.

This is the problem:

The pool leaks!!!

If I have the main drain off and the skimmers on, the pool leaks maybe .75 to 1 inch per day.
If I have the skimmers off and the main drain on, the pool leaks maybe 1.25 to 1.5 inches per day. (edited)
I have not tested this with the pump off.
When the skimmers are on, I see bubbles coming out of the return jet nearest the pool equipment.

I have tried the food color dye test on skimmers, lights and jets and there was nothing definitive.

There appear to be no wet areas around the pool, outside of the concrete deck.

I used a post hole digger to dig a hole about 1 foot deep roughly between the pool equipment and the pool and the soil was not wet or abnormally damp.

The pool equipment seems to be running fine and I have good pressure. Before changing DE it is around 30 and after 15 or so.

Other than the leak, everything works fine.
Thoughts???

All help appreciated,
Best,
Phil

 

[Bama Rambler]

The next thing to do is test it with the pump off.

From your description it's leaking more with the skimmers off. This, and the fact you're seeing bubbles at the returns, leads me to believe the leak's in the skimmer line somewhere.
With the water flowing through the skimmers the head pressure in the skimmer line would be slightly less than it would with the water just sitting there so the leak would be less with it running.

 

[phild]

The next thing to do is test it with the pump off.

From your description it's leaking more with the skimmers off. This, and the fact you're seeing bubbles at the returns, leads me to believe the leak's in the skimmer line somewhere.
With the water flowing through the skimmers the head pressure in the skimmer line would be slightly less than it would with the water just sitting there so the leak would be less with it running.

Thanks for the quick response Bama.

I'll mark the level and turn off the pump and see where it is this time tomorrow.


With the skimmer off and the main on, it leaks more than with the main off and the skimmer on.

 

[Bama Rambler]

With the skimmer off and the main on, it leaks more than with the main off and the skimmer on.

Yeah, you have to think of it backward. When you're pulling through the skimmers the pressure in the pipes will be a little lower than if your not pulling water through them so it would leak less when the pressure is lower. I.E. pulling through the skimmers.

Does that make sense?

 

[phild]

Yes it does make sense.

So, following that logic: With the pump off, the pressure in the skimmer lines will be the same as with pump on, the skimmers off and the main on. Therefore I should expect to see a leak of around 1.25 to 1.5 inches in a 24 hour period. The same as with main only.

If the leak is in the skimmer lines, the only time it will leak less is when the pressure is less. ie, we are sucking on it.

I guess this also explains the bubbles from the return when the skimmer is on???

 

[Melt In The Sun]

yes to all of the above.

 

[phild]

Even though I still have about 4 hours to go on the pump off test, the pool level has dropped 1.2 inches so far. I'm sure it will make 1.5" or so in the next 4 hours.

So Bama, this tends to confirm your hypothesis regarding the skimmer lines.

What is my next step?

 

[Bama Rambler]

Get a couple of winterizing plugs and plug the skimmers and rerun the test. If the skimmer piping is where the leak is, it shouldn't lose any water with them plugged. If you still lose water it's not the skimmer piping.

P.S. Run your pump for a day between tests just to be sure you're chlorinating the water well.

 

[phild]

Great!

Turned the pump back on and adding more water.

Will have the new results Friday morning.

 

[phild]

:|

Now I am really confused.

After 24 hours with the pump off and the skimmer inlets plugged, I lost about 1.75 inches of water.

Things I guess I can do.

I can dive down and put a plug in the main drain.
I can plug the return jets.

I can throw myself in front of a bus now and save the pain and anguish!!.

 

[PoolGuyNJ]

Check for cracks in and around the drain housing too.

Scott

 

[Bama Rambler]

Well you're pretty sure it's not the skimmer piping.


I'd hold off on the bus thing right now. You can't leave us without letting us know what the problem is!

 

[phild]

Closed off the return jets.
Skimmers already closed off.
Pump off.

15 hour test and the water is down about .8 to .9 inches and it did rain (heavy) during this period.

So, I guess we can now say it's not the return lines and it's not the skimmer lines.

Next step is to find a suitable plug and a mask and dive down and plug the main.

Stay tuned for the next exciting episode!!!!

 

[PoolGuyNJ]

While plugging the drain, check the drain pot's edges and insides for cracks. I use a couple of lump hammers with strings to the surface to hold me down and keep me steady. Air in the lungs makes one rather buoyant. Bring a bottle of food coloring down with you to check for departing flow.

Scott

 

[Rangeball]

Way back when I went through a similar process. Finding nothing with the piping, I donned a mask and swam back and forth like I was mowing the bottom of the pool. Found a 2" tear in the liner in the deep end. Patched it and leak stopped. Doesn't sound like you have a liner but maybe the process will help?

From your first post-

strange construction... concrete bottom and fiberglass panels for the sides.

If there is no liner, how are the walls sealed to the concrete bottom? Possibly it's leaking at this connection?

 

[phild]

Hi Scott,

Yes, it is very difficult to stay down, that hammer idea is a good one and I need to go down again to check for cracks etc.

In any case, the

Return jets plugged
Skimmers plugged
Main plugged and
Pump off,

test has been running for 20 hours now and the level drop is 1 inch and I would have thought it would have been more than that if the main drain was not leaking. I'll let it run for the full 14 hours.

So, I'm at a bit of a loss, the only think I can think of is that I have multiple leaks. (main maybe, plus air in the skimmer lines?).

I think my next step is to let the level drop below that of the skimmers to see if its still leaking. If so, then that points be at the lights.

 

[phild]

Hi RangeBall,

when I had the pool partially drained, I carefully went around the sides and joins and sealed anything that looked like it might hint at leaking. So I feel good about that.

I don't feel as confident about the main drain and as PoolGuyNJ says, I need to get back down there with some food coloring and do a better check.

My main concern as this point would be the lights, which in my opinion are a poor design.

The lights appear to be composed of a shell, like a deep cup. This I feel confident I have well sealed (around the edges) to the pool sides. However, one of the lights is a bit like a car sealed beam with a long cable out the back of the light and then through the shell. When I had the pool drained and lights apart, this cable through the shell had been sealed with silicon and I left it alone, unfortunately, perhaps I should have cleaned away the silicon and redone the sealing.

 

[Melt In The Sun]

The lights should be easy to check with food coloring as well.

 

[phild]

The lights should be easy to check with food coloring as well.

Well that was one of the first things I tried, but I could see nothing definitive. I'll try it again.

 

[Melt In The Sun]

I expect they are OK then. With the amount of water you've been losing, I think the dye will be quickly and obviously sucked out at the leaking spot(s).