Pool Leak - agonizing over next steps

[mumgoa]

Hello all,

Really seeking some invaluable advice from the experts here:

1) I suspected a shell leak last fall as the water was receding over a period of a long dry spell after pool closure last September. Since my mesh cover was old, it was suspected to be evaporation through cover. Got cover changed in October. I use bricks/heavy stones to hold the cover in place. Right from Oct through opening pool 3 weeks back the cover stayed intact and stones did not move. A few years ago, when I lost water completely (the hydrostatic valve was a problem), the stones moved and one fell into the pool. Nothing like this happened last season. I did not however check the level when cover was replaced. I suspect the level went down but may have not been significant as the cover stayed on with the stones in place.

2) Water is real hot now and lost just over a 1/4 " today. All articles I read seem to suggest that is in normal range.

3) It does not appear to lose more or less with pump on which is good

4) Since I have been a hawk and have a very adverse feeling towards any leak (including basement), I am worried to death about losing water

5) Have read numerous articles that gunite shells very rarely leak but it is areas around jets, lights and skimmers. These have been dye tested and epoxied

6) I do have some paint issues and my expert pool guy who did the coping is very sure these are cosmetic and not a source of leaks

7) Here are my concerns I wish to get addressed by the experts here (PLEASE):

a) Could there be a leak if cover stayed on and stones did not budge at all? There is physics involved as snow fall on cover would raise the level of the pool and maybe that's what caused the stones to be in place masking a shell leak?
b) How can gunite shell be tested? There are no obvious cracks even hairline ones barring the paint disfigurement issues on the floor
c) I understand 1/4" is a normal leak and will keep an eye on the level though November. After the thick of winter sets in , it is very difficult to check level except for position of the stones holding the cover down. With an active leak of lets say 1/4"/day, I could be down 3 feet from Jan through March. How much water should be in the pool over winter for it to be safe?
d) I have read older gunite pool leach water. Could this be just that?
e) Most importantly, would the house foundation be affected or sinkhole caused losing 3 feet over winter and 1/4" over 4 months of pool season.

Thanks

 

[Texas Splash]

My thoughts:
a - Yes. As you noted, there are other areas where a leak could occur and the cover would have no bearing. For some who experience a large snowfall, the cover could get pushed down which would then squeeze water out of the pool if it wasn't lowered enough, but I don't get the impression that happened to you.
b - The entire shell isn't necessarily tested, just portions throughout. So if you have a leak behind the light niche, that would be tested.
c - We generally recommend never letting a pool get any lower than about 1 foot to the bottom. You never want it completely empty, especially in places that may experience a high water table.
d - Not sure about that. Not something I could place a lot of value on at this point.
e - I suppose that might depend on where the water was leaking, IF there is actually a pool leak underground. Also the direction of seepage would play into that scenario as well.

At this point, I would be inclined to let the water fall a little while the weather is agreeable. A leak will usually show itself where the water stops dropping. So if the leak is in the light niche for example, the water should stop dropping right about that point. Same for any return jet fittings. Now if it's the drain again or the HS valve, you don't want to let it drop that low, but you've had that valve replaced recently, so hopefully that's not an issue.

You could also do the TFP "bucket test" as discussed on the TFP Pool School - Leak Detection page to see if you even have a leak to begin with and that the water drop you're noticing isn't just evaporation.

Hope that helps.