pool leaking just can't work it out

[rustygoat]

Hi folks

Hope someone can help me get my head around this leak I have

It’s a long story & hopefully I’ve taken the steps to show I’ve tried to solve it

Stuff in this font is my thoughts



Skimmer on Left side of pool

Bottom drains at the end of pool

Return & vacuum hose point on Right side of pool

Pump in pit bottom Left

Normally over winter I leave pump connected to pool and all pool valves open (no problems in 20+ yrs)

In Januray pool started losing water, there had been frozen water but not a lot, over time water went down to 30 ins From the top, I found that the main drain valve was closed so I opened it, pool water stays at 30 ins from top, I pipe all the rainwater from house/garage into pool, over time pool water goes up to within 5ins of the top, My thoughts are that the leak is in the main drain pipe( maybe pool water froze with no way out it cracked the pipework) and because no air could get in from valve end the pressure of the pool water kept pushing the water out of the pool until I opened the main drain valve and then the air pressure stop the pool water coming out the pool water stays at 13ins below the top of the pool for some weeks, suggests to me leak is in main drain pipework 13ins below top of pool, I take water level down to 16ins below and replace pipework to depth of 15ins problem should be sorted let pool fill with rain water stays at 5 ins below top for 3 weeks, now I turn pump on, with pool water coming from main drain only and going back via return, pumped for 6hrs a day 2 days water level drops 2ins (losing 200+ gals) there must be another hair line leak in return pipe that only shows under pump pressure remove all paving and soil to expose return (and vacuum point pipework) run pump for 4 hrs water drops ½ in no leaks on main drain, return or vacuum hose pipework how can this not leak looking in the pump pit the wall facing the skimmer shows signs of damp but if the skimmer pipework was leaking the water level would not have stayed at 5 ins from the top, also the skimmer valve at the pump end is closed so its not pressurising the skimmer pipework when the pump was running

Yes next step is to expose the pipework to the skimmer, but I don’t understand why if it has a leak the water level stayed at 5 ins below the top for some weeks, and why the water level went down when the pump was running but the skimmer valve was closed

 

[Texas Splash]

There is a lot to address in this scenario, but it might also help to see some pics of the pool from various angles. The equipment pad as well.

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

 

[rustygoat]

 

[rustygoat]

3 photos of the pump pit, (yes I know its old and untidy but its been working ok for years)
First photo shows the valves from the pool top valve is vacuum pipe, second is main drain, bottom is skimer, may be able to see wall looks damp below the skimer valve
second photo is roughly same view
third photo is other wall of pukp pit which shows the damp
as I said water level dropped to -30 ins, opened the main drain valve, rainwater filled pool to -13ins, new pipework fitted to top section on main drain pipework (roughly 15ins deep) water level now stays around -5 ins, run pump water level drops -7 ins (pipework and filter can't hold the 200missing gallons, patio removed to see pipework pump run no water leaks seen, but water level dropped by about 1/2 ins (roughly 50 gals) pool is 12ft x 24ft

 

[Texas Splash]

Something does seem odd. Do you have any leak detection DIY tools around to help? Sounds like you are focused on the plumbing itself, and for good reason. But don't rule out other areas as well though to be safe. Do you have a way to try any pressure testing of the lines, or are you relying 100% on digging and visual inspections? Visual is fine for pressure lines, at least as far as you can get to.

 

[rustygoat]

no leak detection kit, its just visual inspection
as water only now drops when pump has been running,( only pipes with raised pressure would be main drain pipework & return pipework) only thing that may make sense is the main drain pipework may have another hairline crack further down the pipework
what do you think ?

 

[Texas Splash]

If you are sure the water loss happens only when the pump is running, I would focus on the return jets and the line going to those jets. The main drain should only show water loss when the pump is off in a static mode. If you still have concerns about that drain line, try to isolate it with a winterizing plug in the drain and closing the valve.

 

[rustygoat]

I have exposed the return lines & the vaccum line pipework can'i see any problems
my idea now is to carry out a few tests (unfortunately becuase the water level has dropped and no rain coming soon have to hope leak will still show)
close valve from main drain to pump, then in turn pump the water from vaccum outlet, then skimmer outlet, if no water loss points to main drain pipework, then run water from main drain to retrun pipework is water level goes down (hopefully) its a crack in main drain pipework

 

[rustygoat]

I'm still stuck on this leak, locally hard to pick up pipe fittings to make a DIY leak detector using air
I've found what looks like a crack in pipe fitting on main drain pipework (photo below)

water level had dropped to 10ins below top of pool
run pump for 2 x 5 hr sessions water level staied at 10ins below top of pool (why is water staying at this level ?)
water level is below skimmer skimmer pipework still holding water ( valve pump end closed)
had some rain over last few days ( water level now 8 1/2 ins below to of pool)
read some acticles that say if leak when pump running it points to leak in rtn lines ( yes they will have pressure but surely the pump sucking water from main drain pipework will increase pressure in that pipework ?)

really finding this hard brain work so any tips or advice,

now water level is above 10ins below top of pool, and the crack in pipe fitting is exposed I'm thinking run pump with main drain pipework open & rtn open, Skimmer & vacuum pipework closed, hope then that crack in pipe fitting leaks (concern is because it lost so much water on the tests before eg 2tns of water lost, then this little crack is not only fault)

 

[Texas Splash]

Leak detection can be tricky. Hope you can find the bad area(s). If not, you might have to call-in the pros.