Overnight Water Loss w/pump off

[George D]

Hello,
What would cause overnight water loss, only when the pump is off?
The pump does not lose prime after I turn it off. There waste port is not leaking.

Thanks.

 

[mknauss]

Evaporation. Below water level leak.

Pool School - Leak Detection

 

[mas985]

What would cause overnight water loss, only when the pump is off?

I would suspect a suction side leak and probably underground, unless you see the water leaking out somewhere when the pump is off.

When the pump is running, do you get air in the pump basket?

 

[Catanzaro]

Hello,
What would cause overnight water loss, only when the pump is off?
The pump does not lose prime after I turn it off. There waste port is not leaking.

Thanks.

How much water are you losing, and is this only when pump is off? When exactly did this start?

 

[George D]

When the pump is running I don't see bubbles and there is no air getting in the pump basket. After I turn the pump off, the water stays in the pump basket when the valve is at 50% skimmers(2 skimmers) and 50% drain.

I think it started about 2 weeks ago. About 1/2 inch per night but it varies. Last night when it rained, the water level went up. Yes, this only happens while the pump is off.

 

[George D]

Any ideas?

 

[mknauss]

With pump off would imply a suction side leak that is below the water level in the pool. Skimmer?

 

[mas985]

I think it started about 2 weeks ago. About 1/2 inch per night but it varies. Last night when it rained, the water level went up. Yes, this only happens while the pump is off.

1/2" is a lot in a night but have you done a bucket test to confirm it is indeed a leak?

Also, how are you measuring this?

Do you have an auto-fill and/or overflow?

 

[Catanzaro]

I think it started about 2 weeks ago. About 1/2 inch per night but it varies. Last night when it rained, the water level went up. Yes, this only happens while the pump is off.

This is normal. As Mark mentioned, have you done a bucket test. I like the blue painters tape on the skimmer test. Also, with pump off, water, based on elevation of pump gets back into the pool. The pool is 2' below the equipment pad, let alone 3-5 feet from the highest points on the plumbing. I know that when the filter turns on and water is moving that the water on the steps is less. With the pump off, and water calm, the level is definitely higher.

I keep my water at least 2" above the skimmer as nuts drop from this tree and stain the steps without water. Then I have to pull out the magic eraser.

 

[George D]

I measured using a tape measure but I will try the bucket test.
No, I do not have an auto fill or overflow drain. I add water manually with a hose.
Where exactly do I place the blue painters tape?
I noticed today that the chlorinator is slowly leaking while the pump is on.

 

[George D]

Bucket test confirmed there is a leak when pump is off. Should I purchase the leak detection dye and add some near the skimmers?
The pump does not lose prime. Could it be the liner?

 

[mas985]

Could be any penetration point of the liner. Skimmers, returns, MD, etc. Could be something else too.

 

[George D]

Ok, Thanks. I will try the leak detection dye near the skimmers. If I don't see a leak there, I guess my only option would be to hire leak detection specialists.
What is MD?
If the liner is leaking why is there no water loss when the pump is on?

 

[Kiss4aFrog]

Have you checked out some of the videos on leak testing on Youtube. I love show and tell.

 

[mas985]

What is MD?

Main drain

If the liner is leaking why is there no water loss when the pump is on?

Good point. I had forgotten about that. That generally points to a plumbing issue. Without the pump running would point to a suction side leak.

 

[George D]

Would a Main Drain leak show in the waste port? The waste port shows no signs of leaking.
The pump operates smoothly with no signs of air and bubbles and does not lose Prime. The only bubbles I see are at the returns, as soon as I turn on the pump. This only lasts a few seconds. Is this another indication of a suction side leak?
I read the Pool School link on suction side leaks and the only thing that I could not find is the two drain plugs in the pump. I found only one.

 

[JamesW]

Try this:
1) Remove pump lid. Important.
2) Get a plug that will thread into the bottom of the skimmer in the line going to the pump. Drill a 1/8” hole in the plug.
3) Screw plug into the bottom of the skimmer in the line going to the pump.
4) Plug any other skimmers with a regular plug.
5) Squirt a tiny amount of dye near the hole in the plug.
If the lines are leaking, the dye will be sucked into the hole. If they aren’t, the dye will not get sucked in.

Any type of non-toxic dye will work. Food coloring etc.

Even one of the colored test reagents would work. Just don't reuse for testing because the reagent gets diluted with pool water. Maybe a bottle with just a tiny bit left.

An oral syringe (like for giving babies medicine) is a good way to control the dye. Just put some dye in the syringe and squirt the dye close to the hole. You can get the syringe at any drugstore or general store.

Looking straight at the superpump, there is one plug at the front center and one on the right side.

 

[George D]

Thanks. I will try this.

 

[George D]

Before doing the plug test I tried to take care of both pump drain plugs. I lubed the o-ring on the side plug and replaced the teflon tape on the front plug. . I made the problem worse. Now my pump loses Prime as soon as I turn off the pump. I unscrewed the front plug and removed some teflon tape and nothing. This takes huuuge patience.

- - - Updated - - -

Before doing the plug test I tried to take care of both pump drain plugs. I lubed the o-ring on the side plug and replaced the teflon tape on the front plug. . I made the problem worse. Now my pump loses Prime as soon as I turn off the pump. I unscrewed the front plug and removed some teflon tape and nothing. This takes huuuge patience.

 

[mas985]

By front plug, do you mean the one under the pump basket as that one is on the suction side and would affect the priming of the pump. The plug on the same side as the motor is on the pressure side of the pump so it would leak out.

If it was the pump basket plug, then look closely at the housing near the plug. Sometimes it will crack making seal nearly impossible. Those will also leak when the pump is off.