Help! Backwashed you drop water level below skimmer but it dropped another inch?

[2thdoc1]

So we have a pool company coming today to close our pool. They wanted the pool drained to just below the skimmer. I backwashed this morning and lowered it to the bottom of the skimmer plate, then turned the pump off. I just went out there an hour later and the water level now looks to be an inch below where I stopped backwashing? Is this normal? What could cause that to happen? We’re in Michigan and expecting a ton of snow so I’m not worried about the level being too low, but now my returns are halfway uncovered.

 

[mknauss]

Did you take the MPV out of backwash and back to filter?

 

[2thdoc1]

I just did that now. Would leaving it in backwash even with the pump off cause it to continue to drain?

 

[mknauss]

Yes. It was siphoning out. It should now stop if you put on filter.

 

[2thdoc1]

Thank you so much! I feel a bit silly now. I’m planning on watching the closing this year in hopes of doing it myself next fall. Our pool builder who closed it the past 2 years has apparently fallen off the face of the earth, so had to find someone to come out last minute. Do you think the water level will be ok about an inch below the skimmer for a fiberglass pool?

 

[mknauss]

I am not a pool closing expert. So ask the closing company -- will also tag @ajw22 as he closes his pool.

 

[JamesW]

Based on this picture, the waste line goes into the ground to somewhere.

A line like this should have a vacuum breaker installed.

Without a vacuum breaker, the line will not drain and it will water hammer as the multiport is moved especially if the waste line is long and the end is much lower than the filter.

Where does the line go?

https://www.lowes.com/pd/Watts-N36-Brass-MNPT-3-4-in-Vacuum-Breaker/3503158

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