In ground liner pool possibly leaking?

[likwid]

Been doing the "Bucket test" and it seem like I lose 1/2 inch in the pool and only 1/4 of an inch in the bucket. But here is the interesting part, I only lose water overnight.

I filled up the pool to were i wanted and marked it 9AM in the morning. I left the pump on for 5 hours and turned off it. No water loss (2PM). at 8PM i checked the level and no water loss. 9AM the next morning 1/2 inch water loss.

Next morning I did the same thing and filled it up to the point it should be but did not start the pump. All day again NO water loss my last check was at 930PM (12 hours) no water loss. The next morning exactly the same amount 1/2 inch.

We had a heat wave where it went to 104 degrees for about 3 to 4 days and my pool temp raised to about 85 degrees. These last few days the temp has been around 85 to 90 outside and dropping to low 70's at night. I have heard that sudden drops in temp when the pool is warm can cause massive evaporation at night. Not really sure about this.

I can say that the bucket never seems to lose much water. I have found 3 giant holes in the liner that I patched well before any of this started. No air bubbles, no losing prime.

I don't have any dye that I can check the patching with. Would a grocery store or Home depot place have something I can use? I tried the PH drops but they don't last long in the water. I tired to place them as close to the holes i patched and they don't really move much.

The only thing that is odd is the water loss only overnight and not during the day. If it was a hole that I failed to find/patch right I would think I'd lose water during the day as well.

 

[Bama Rambler]

Does your pump run at night on a timer?

You can use gel food coloring. It works better than the liquid but if that's all they have you can use it.

 

[likwid]

Pump is not on a timer.

 

[Bama Rambler]

Run the bucket test with the pump running and then again with it off. It could be that you have a suction side leak and it doesn't leak with the pump running. Are there air bubbles in the pump basket when it's running?

 

[likwid]

No bubbles in the basket. Liner is about 6 years old now.

I did not run the pump all day one day and did not lose a drop (to say) but overnight it seem to lose 1/2 inch (pump still off). I'll investigate some more tonight and see.

 

[Bama Rambler]

What's the temp difference there between day and night? (yeah, I'm grasping here)

 

[likwid]

tonight when i got home I lost 1/4th of an inch (along with the bucket) so that lines up. Perhaps it really is due to the outside temp.

it been in the high 90's during the day and dropping to the low 60 sometimes high 58's overnight. Pool temp is at 86 degrees.

 

[likwid]

Just in case somebody is searching might find this useful.

This morning I lost another .5 inches overnight. The bucket lost zero. However the Temp of the bucket vs the pool are significantly different. I obviously filled up the bucket with the pool water before the end of the night so the temp started the same.

Pool 85 degrees
Bucket 70 (matching the morning air).

Defiantly has to be a case of high temps during the day and massive change in temps at night. Covering the pool up at night and seeing if I lose anything in the morning will prove this. If it was not such a hassel I might do it. But losing 500 or so gallons might make the hassle cost effective.

 

[Bama Rambler]

So you haven't been setting the bucket on the steps in the pool water?

We lose significantly more water at night here than we do during the day.

 

[likwid]

I haven't been able to put the bucket in the water, guess that what I have been doing wrong. My current bucket even on the first step is not big enough to not be submerged. I put it on the diving board.

I'll have to give that a go.