Puzzled by water loss over winter

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Kurtomac

Well-known member
Nov 18, 2019
73
Maryville, TN
Good morning,

I have a 18x36 in ground liner pool with a 9-year-old liner. I pulled my solid cover off about a week ago and was surprised to see only about 6" of water left in the shallow end. Luckily it didn't let go and its finally full and got everything up and running. I don't understand where my water went, it didn't appear to be leaking at time of closing and after filling it doesn't appear to be leaking now. I did a bucket test last night (12-hour test) and saw no loss in the bucket water and no loss in the pool water that I could tell. I have a leak detection company lined up to come out on Wednesday but now I kind of think I should just cancel it and save myself the $600 fee. So....where did my water go? I keep an auto pump on top of the cover all winter long. Last spring when I opened the pool it was low, but I had added water some throughout the winter but didn't do so this winter. I wasn't expecting 13,000 gallons to be gone. I had to add all that water, 4lbs of CYA, 400lbs of salt, and 3 gallons of chlorine to get me going. My 3-year-old RJ 60+ controller keypad took a dump over the winter as did my flow switch...I kind of thought this stuff would have lasted longer.

My hypothesis:

Water evaporates out of the pool and on to the underside of the cover and then the pump slowly sucks it through the cover. Thoughts? The pool was closed for 6 months. Is this normal? This cover is 2 years old and having just a tarp and water bags the year prior, I didn't have this issue. I don't want to have to add 15k gallons of water and all this CYA and salt every spring and it surely isn't good for my old liner to be that low for that long. I was hoping to squeeze a couple more seasons out of my liner, it is getting pretty faded out in areas but overall seems to be ok.

Thanks fellas70274784308__71269E16-9A47-4E02-86D4-C76426CF457D.JPGIMG_0878.JPG70274825077__2BFB23AF-BAD8-42D8-9088-7033ADA53F6E.JPGIMG_8858.JPG
 
Last edited:
Kurtomac said:
Good morning,

I have a 18x36 in ground liner pool with a 9-year-old liner. I pulled my solid cover off about a week ago and was surprised to see only about 6" of water left in the shallow end. Luckily it didn't let go and its finally full and got everything up and running. I don't understand where my water went, it didn't appear to be leaking at time of closing and after filling it doesn't appear to be leaking now. I did a bucket test last night (12-hour test) and saw no loss in the bucket water and no loss in the pool water that I could tell. I have a leak detection company lined up to come out on Wednesday but now I kind of think I should just cancel it and save myself the $600 fee. So....where did my water go? I keep an auto pump on top of the cover all winter long. Last spring when I opened the pool it was low, but I had added water some throughout the winter but didn't do so this winter. I wasn't expecting 13,000 gallons to be gone. I had to add all that water, 4lbs of CYA, 400lbs of salt, and 3 gallons of chlorine to get me going. My 3-year-old RJ 60+ controller keypad took a dump over the winter as did my flow switch...I kind of thought this stuff would have lasted longer.

My hypothesis:

Water evaporates out of the pool and on to the underside of the cover and then the pump slowly sucks it through the cover. Thoughts? The pool was closed for 6 months. Is this normal? This cover is 2 years old and having just a tarp and water bags the year prior, I didn't have this issue. I don't want to have to add 15k gallons of water and all this CYA and salt every spring and it surely isn't good for my old liner to be that low for that long. I was hoping to squeeze a couple more seasons out of my liner, it is getting pretty faded out in areas but overall seems to be ok.

Thanks fellas
Click to expand...
It went somewhere and it wasn’t from evaporation. (I left mine uncovered all winter and lost very little ) I’d keep the leak detector appt.
 
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It certainly is possible the pump on top of your cover resulted in some water loss. It's happened to many others, but with only 6" left at opening, I'm sure the cover didn't drop that low to result in water loss. :scratch: Seems unlikely that's the main culprit. Infesting however you lost no water after refill (yet). I'd watch it over the weekend. Don't cancel the appointment quite yet.

As for the RJ, that's a shame. You still have some pro-rated time on it, so you might do an exchange soon to get as much value as you can from it.
 
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Texas Splash said:
It certainly is possible the pump on top of your cover resulted in some water loss. It's happened to many others, but with only 6" left at opening, I'm sure the cover didn't drop that low to result in water loss. :scratch: Seems unlikely that's the main culprit. Infesting however you lost no water after refill (yet). I'd watch it over the weekend. Don't cancel the appointment quite yet.

As for the RJ, that's a shame. You still have some pro-rated time on it, so you might do an exchange soon to get as much value as you can from it.
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I got some pro-rated warranty on the parts, now I gotta tear apart this controller and install the keypad (this also worked fine at closing). Its weird only about half of the buttons work on it.
 
Kurtomac said:
Checked bucket last night and both pool and bucket were down approx 1/8” after 24 hours
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That seems reassuring from an active leak perspective, but still doesn't explain the large loss over the winter. Interesting. :scratch:
 
If it's truly stopped at that height, I'd wager the bottom of the stairs is the leak and it evaporated the other inch or two. Or the leak is below that level and you've found the ground water level so it had nowhere to leak to.
 
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I think your cover has a leak. Where exactly do you put the cover pump during the winter?

I also lose water before opening and I know it’s my solid cover’s small hole and where I put the cover pump.

When I opened last week I dropped the pump to the second step and pumped a lot of water from above and below the cover out. I then observed that the top step is basically perfectly lined up to the bottom of the skimmer trim. In future years I’m going to manage the off season water to the top step, and as each year passes I care less and less about the water on the cover.

In prior years I’d put the pump dead center in the pool and my water level would clearly drop every time I turned the pump on. I know my cover has a leak, but, a) I’m too cheap to replace, and b) who’s to say the next one won’t leak?
 

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Kurtomac said:
Would you cancel the leak detection people and just watch it over the next month?
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Tough call. Why toss out money for nothing right? If the water level hasn't dropped for the past few days, it almost seems fruitless.

I don't think we asked this question, but is there any chance water may have leaked out from your waste port by mistake?
 
Maybe not worth trying to recreate the scene of the crime by putting the cover back on along with the pump and see if you can make it happen again? Did you leave some of the plumbing knobs open such that a siphon would slowly lower the level all winter?
 
Bperry said:
Maybe not worth trying to recreate the scene of the crime by putting the cover back on along with the pump and see if you can make it happen again? Did you leave some of the plumbing knobs open such that a siphon would slowly lower the level all winter?
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The bottom drain was air locked and the equipment pad is a few feet above pool level. The returns were all plugged off also.
 
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Kurtomac said:
It was sagging some
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You would have seen the difference because at any level, the cover would have to dip back to the water level to suck more out.

This is very possible without noticing. A heavy rain or snow/ice holds the cover down while it pumps pool water. But any further than 18 inches will likely damage the cover. They can only stretch so far.

Screenshot_20230423_110519_Chrome.jpg



it would not have made it this far

Screenshot_20230423_110519_Chrome.jpg
 
rmclain73 said:
I have a very similar situation going on up here in the Boston area. Did you ever find a leak? Most of my water disappeared over the winter. Filled it, now its holding fine.
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I cancelled my appointment with the leak detection company. I’ve given it another couple weeks. Seem to be losing a slight amount maybe. My salt level is slightly down and we’ve not used the pool or backwashed the filter. Looks like I may have them come out after all
 
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Kurtomac said:
I cancelled my appointment with the leak detection company. I’ve given it another couple weeks. Seem to be losing a slight amount maybe. My salt level is slightly down and we’ve not used the pool or backwashed the filter. Looks like I may have them come out after all
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My leak hid within my more heavy evaporation rate season to the point PB and I vacillated on this issue for many months. A very slow calcium loss, and a little CYA as well, was telling me what really was going on. I'd get the leak detection company.
 

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