Help: water level dropping in closed pool

arvpoolnj

Member
May 1, 2019
7
Glen Rock, NJ
Hi everyone, I closed my pool this season (about 1.5 months ago) on my own following the instructions on this site. Today, I noticed the water level seems a decent bit lower than I closed it. It might have been dropping for a while, but today, I went out to check it and it is indeed lower. I closed 2 inches below the bottom of the skimmer, but now its 6 inches below at least and the water level is just at the top of the returns. So Im pretty sure it has dropped since when I closed it. I would have expected no water level drop since I have a non-permeable tarp (from ULine). Is it possible that its evaporation or is there the potential for a more serious issue?

I have noticed that the antifreeze that I poured into the skimmer around the gizmo is missing. Could it gradually drain down?

Is there anything I need to do immediately to protect the pool? To me, the worst case is that the water is now back in the lines somehow, perhaps leaking thru the plugs? Is that possible?

Its hard to explain that much water just filling into the lines right? The temperature has just touched freezing a couple of nights in the last week, so Im concerned that I need to act fast.

Any help appreciated.

Pool details:
- Location: Northern NJ
- concrete, square
- 2 skimmers, 3 returns, 1 in stem and 2 opposite the skimmers, 1 side wall
- Closing details: lowered to 2 inch below the skimmer. Blew lines out with a shop vac starting at skimmer, pool first, then equipment.
 

ajw22

Gold Supporter
TFP Guide
Jul 21, 2013
10,746
Northern NJ
It is unlikely that amount of water went into your plumbing. More likely you have a leak that was masked during the season by rain and normal water addition.

I would monitor the water level and see where it stabilizes. That will be a good indication of around where the leak is.

The cold temperatures right now in NJ are not enough to cause freezing damage. Read...

 

wireform

Silver Supporter
In The Industry
Aug 15, 2017
486
Spring Valley, NY
What AJ said but will add some insurance here. In order to rule out a masked pool problem as AJ claims, check the open pool lines where ever they are and probably at the pool equipment pad if not somewhere in between. It is a slow leak and one or more of the plugs aren't holding well. Check to see if you find a wet spot wherever these lines end. Now that it hasn't rained in a few days it'll be easy to spot. To me it sounds like it's the first time closing and those plugs are tricky. I would say what ever you have in the skimmer leaked out the antifreeze and that needs attention. Your best bet may be to redo the winterizing in the pipes as it may be hard to tell where your problem point is and it doesn't matter once water is back all the lines need to be blown again.
 

Catanzaro

Platinum Supporter
TFP Guide
Jul 30, 2014
3,401
Monmouth County, New Jersey
Arvpoolnj:

Did you ever investigate this problem? I would personally clear the lines again, and fill the pool back up to the normal level and then monitor the situation. What type of cover do you have? What type of pool? Please add your signature as well. If you have a leak somewhere, you would be surprised how much water can actually go back in the lines. The lines will hold a lot of water, but lets take one step at a time.

Last year, I lowered the water below the skimmer (1"), cleared the lines and moved on. I have a solid tarp and about 2 months later, I pumped water off the cover (twice at different time) and noticed the cover was down further than normal. I peeked underneath and realized that the water level had gone to the returns (maybe below the returns). I was worried at the weather was cold and I had lost at least 6", maybe more. I quickly filled up the water back to half way on the skimmers and left it alone. I monitored the water level, including the water on the cover. There was no water truly coming through the cover.

Therefore, it was a leak or the cover was ripped. Guess what, neither. I am guessing that evaporation, especially as the water remains warm under the cover, and the air temperature drops can happen even through the winter, but I could be wrong. Unless the winter plugs leaked (very possible), skimmer lines leaked (very possible), and/or the main drain did not hold the seal. But I remember air escaping in the main drain, but could not verify the water in the skimmers or return lines. Considering I have 2" pluming a lot of water could have entered those lines, but at 6", we are talking about 1,500 gallons (roughly), so between evaporation and a leak, it could have been possible.

During the summer and season, for about 7 months, there were no leaks. This year, I decided not to lower the water, but kept half way up the skimmer. I have not pumped any water off the cover and am allowing to fill up, and from what I can tell, there has been little to no evaporation. So, in the end, it is very difficult to tell what happened.

Good luck and keep us posted on what you do. Thanks!
 

arvpoolnj

Member
May 1, 2019
7
Glen Rock, NJ
Interesting, thanks so much for all the inputs. Apologies for not adding my signature, added now. And yes, this was my first time closing. I have done some more investigation.

1) The water is a bit lower again today, perhaps a 1/4 inch or so. My side wall suction plug's green twist handle is more exposed than previously.

2) No wet spots at equipment. The valve that controls the skimmers is set to open on the "equipment side" skimmer and closed on the "far side" skimmer", which would allow any water from the skimmer to pass into the equipment pad. But I verified that there is no water in the pump basket. So that means if water is filling the plumbing, its not enough to leak thru into the equipment. Also all the return valves to the returns are closed.

3) I had put anti-freeze around both gizmos, about a 1/3 of a gallon in each. Both dont show any anti-freeze (perhaps thru the closed off 2nd hole in the bottom of the skimmer??) I have the "deluxe gizmos" that have the small cap at the top for blow outs.

===>> 4) The "equipment side skimmer" was almost filled with water. That seems really weird. I dont get how it could fill with water especially since I lowered the water to 2 inches below the skimmer. But at the beginning of the season, this skimmer was leaking. It had somehow peeled off the pool wall, so water was entering it, and leaking out. This was "fixed" by a pool company at the beginning of the summer. If anything, this seems like a culprit, but I dont understand how it could be an issue if the water is below the skimmer. Perhaps enough rain water entered it from the top? The water inside was almost upto the weir line. I just emptied it out by hand.

5) Just to check, I opened the valve at the top of the gizmo. When I opened it there was an audible release of air, like a sigh. This seems to maybe indicate that it was sealed well?

So right now, there are 3 theories I guess:

- Skimmer leakage (but dont get how it could really happen since water is below skimmer line)
- Not fully plugged return lines (but I would have seen water at the pad)
- Evaporation?

Perhaps having the pool service come tomorrow is my best bet, I was really hoping to get thru the whole season without them, but this seems like a risky situation given the weather...
 

wireform

Silver Supporter
In The Industry
Aug 15, 2017
486
Spring Valley, NY
You could use some water colorant and carefully drop it next to each return to see if it disappears into one of them. Also, not sure of "no water in pump basket"? How is the equipment pad, higher or lower then the pool. If it lower I can see the pump basket being an indicator but assuming it's higher then the pool the only way to get water to the pump basket would be via suction so I'm not sure what's happening. No mention of a main drain but if yes can be hydrostatic valve leak which happens too.
 
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arvpoolnj

Member
May 1, 2019
7
Glen Rock, NJ
Ok, I will see if I can find the colorant. Some additional responses below:

- no main drain
- equipment pad is at same level as pool
- I went under the tarp to see if I could see a clear water line. There was a dry area on the pool wall 2 inches below the skimmer, which is where I closed the pool. But the water is now almost a foot below that point. In a 20x40 pool, that is almost 5K gallons? So its hard to imagine that much water is in the lines somewhere since the equipment pad is only 20-30 feet away from the pool.
 

arvpoolnj

Member
May 1, 2019
7
Glen Rock, NJ
Original structure is probably 70s, but it was re-plastered and re-plumbed in summer 2017. On both Spring openings in the last 2 years I had lower water levels. This is the first time I have closed myself so im paying more attention to it.

This year, on the opening, the skimmer was leaking (see posting above) and I had it fixed.
 

ajw22

Gold Supporter
TFP Guide
Jul 21, 2013
10,746
Northern NJ
Original structure is probably 70s, but it was re-plastered and re-plumbed in summer 2017. On both Spring openings in the last 2 years I had lower water levels. This is the first time I have closed myself so im paying more attention to it.
That is interesting since my pool water is always higher then when closed due to rain water and snow melt. Last year we had so much rain I needed to drain my pool twice to keep it from overflowing.

I suspect you have a leak problem from the replaster. Either around the lights or returns.