Losing water under pool cover

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maw9110
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Posts: 5
Joined: Mon 31 Dec, 2018 10:58
My Pool: Inground 20,000 gallon rectangle vinyl liner pool with sand filter

Losing water under pool cover

Postby maw9110 » Mon 31 Dec, 2018 11:12

Hi all and Happy New Year,

This year was my first year to close my pool for the winter as I live in the south and do not have a harsh winter. However, I discovered that I have been losing water slowly underneath my pool cover and have been working to try to diagnose the issue. I closed the pool using a vynl pool cover and water bags. I did purchase a pump to remove water from the cover as well. Recently I have filled my pool back to operating level, removed the water pump (in the event that it was pulling pool water), and taped my water level to mark it. After 12 hours I noticed that I have lost about an inch of water undeneath the cover. This would indicate that I have a leak in the plumping or pool liner? I have not noticed any floating of my pool liner as well. I have not noticed any issues prior to closing also.

My last theory, when I closed the pool I left the pool setting in between filter and waste as I do not have a winter setting on my sand filter. Is it possible that I am slowly draining water from the main drain to waste? In the past I made a bone head mistake and left my pump off and in waste setting after vaccuming and I lost about half my pool water overnight.

Sorry for the lengthy desrcription and thank you for any help!

Michael


Teapot
Pool Industry Leader
Pool Industry Leader
Posts: 1337
Joined: Tue 17 Oct, 2017 10:52
My Pool: 12 x 24 (45m3) liner pool, Triton TR60 filter with AFM glass media (Activate) and variable speed pump running 0.08HP
Location: UK

Re: Losing water under pool cover

Postby Teapot » Tue 01 Jan, 2019 03:21

Don't leave the valve in mid position. Is the filter above or below the water level?
maw9110
I'm new here
I'm new here
Posts: 5
Joined: Mon 31 Dec, 2018 10:58
My Pool: Inground 20,000 gallon rectangle vinyl liner pool with sand filter

Re: Losing water under pool cover

Postby maw9110 » Wed 02 Jan, 2019 10:39

Teapot wrote:Don't leave the valve in mid position. Is the filter above or below the water level?


The filter is pretty much level with the pool, maybe a half foot lower than the water level.
Teapot
Pool Industry Leader
Pool Industry Leader
Posts: 1337
Joined: Tue 17 Oct, 2017 10:52
My Pool: 12 x 24 (45m3) liner pool, Triton TR60 filter with AFM glass media (Activate) and variable speed pump running 0.08HP
Location: UK

Re: Losing water under pool cover

Postby Teapot » Thu 03 Jan, 2019 12:22

Ok, do you have a valve to seal off the backwash pipe, other than the multiport?
A lady years ago inadvertently caused a siphon action and managed to drain almost the entire pool!
What id is turn off the valve fitted before the pump, then drain the filter for winter. The overflow on the skimmer sorts out the water level.

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