Winter leak?

[EricV]

I think I have a leak in my pond that developed this winter. Just looking for ideas. Here's the background.

I have an overflow in my skimmer, so when I shut down my pond for the winter, I expected to lose about an inch of water from the pond. That's because the draw from the pump was keeping the water level inside the skimmer about an inch below the pond surface. That happened for sure.

The last few weeks the surface has been further down than I expect and inside the skimmer it does not come up to the level of the inside of the overflow bulkhead. For some reason, the skimmer also bows in a bit near the overflow bulkhead. Over the weekend I put another inch or so of water into the pond, but it seems the level has dropped again. (It's kind of hard to tell since the pond is iced over. That makes it hard to tell what the actual water level is.)

So, if I have a leak, I can really think of just a few places, all related to the skimmer.

a) a crack in the skimmer
b) around where the liner attaches to the skimmer
c) maybe the bulkhead is no longer making a good seal on the skimmer and water is coming out at the bottom of the bulkhead cutout.
d) I suppose I could have a hole in the liner somewhere else in the pond.

Any ideas of what I can check? Am I needlessly fretting and should just wait until everything thaws out?

 

[Meyer Jordan]

Just curious. What is the width of the skimmer weir opening and what is the flow rate of your pump?

 

[EricV]

It's an EasyPro Small, so 8" weir. Pump is TidalWave3 6000 gph, but probably well under 5000 gph once you account for the actual head and pressure from the plumbing. The skimmer is rated for 6000 gph

 

[Meyer Jordan]

It's an EasyPro Small, so 8" weir. Pump is TidalWave3 6000 gph, but probably well under 5000 gph once you account for the actual head and pressure from the plumbing. The skimmer is rated for 6000 gph

When you stated that the water level in the skimmer was usually about an inch below the pond's water level I suspected that you were pushing the flow limit on the skimmer and, as you are already aware of, it makes it difficult to determine the actual water level in your pond especially with it being iced-over.
I suggest turning the pump off for at least one day and monitor for any changes in the water level. If you find no change either you do not have a leak or it is around the waterfall (usual culprit) or in the plumbing (doubtful).

Sorry. Just re-read your original post. You already have the pump turned off with Winter shut-down.
What do you estimate the water loss to be (in inches) per day?

 

[EricV]

Oh, the pump is out. Has been for weeks. It's the drop *after* that that I'm worried about. So it can't be the waterfall or plumbing, there is no flow. And if the overflow is still functioning, the water level inside the skimmer should come up exactly to the inside threads of the overflow bulkhead.

Next up will be a more controlled experiment where I put some more water in (enough to submerge all the ice) and measure the exact level in the skimmer box and then see if it drops again and how quickly using a ruler inside the skimmer box.

I don't want to add too much untreated tap water at any point though.

 

[EricV]

Well, I definitely have a leak. I put an inch of water in the pond last night and by this morning it was gone. It's not the overflow bulkhead as the level drops well below that. While it's hard to tell, I don't see any cracks in the skimmer box at the water line. But I tried shoving a thin wooden stake into the soil around the skimmer and it penetrates easily, so I think it's around there.

Under the assumption that it's the liner connection to the skimmer, should I first try tightening the bolts again? If not or that doesn't work, can I disassemble the connection, pull off the old silicone and just redo it or do I need to cut a new hole in the liner?

 

[Meyer Jordan]

Well, I definitely have a leak. I put an inch of water in the pond last night and by this morning it was gone. It's not the overflow bulkhead as the level drops well below that. While it's hard to tell, I don't see any cracks in the skimmer box at the water line. But I tried shoving a thin wooden stake into the soil around the skimmer and it penetrates easily, so I think it's around there.

Under the assumption that it's the liner connection to the skimmer, should I first try tightening the bolts again? If not or that doesn't work, can I disassemble the connection, pull off the old silicone and just redo it or do I need to cut a new hole in the liner?

No need to cut a new opening in the liner. The skimmer weir faceplate can be re-sealed if this is indeed where the leak is.

 

[EricV]

Thanks. Good to know. I'll wait until the weather is warmer and then take good look including seeing if it really very wet near the skimmer. I could probably even run the pond as it is as there is still a couple of inches of water in the weir opening. Maybe with a lower volume pump if needed.