How to find a leak in a liner?

[Johnnie]

Ponders, how do you detect and find a slow leak in an 1.5-year-old-liner?

The water level drops 3/8th of an inch in depth per day. That's 6 inch-drop after 16 days per the above yard stick shown in the photo.

I'm 100% sure that my liner leaks after I fixed up the tiny-tiny dripping problems in the check valve and other filter-hose-connections.

Hmm... I don't mind to "change" and refill 6 inches of water every 16 days now, but not during the winter! Hmm... I'll better find and patch up the leak... or my pond will leak and dry up completely in 96 days during the Winter per table below.

		Refilled in	7x7x3x7.48	

Refilled-		Ounces of	Refilled in	Pond 

Depth in	Refilled	ClorAm-X	Gallons	dries up

Inches	%	4.68	1100	in days



1	0.03	0.13	31	

2	0.06	0.26	61	

3	0.08	0.39	92	

4	0.11	0.52	122	

5	0.14	0.65	153	

6	0.17	0.78	183	

7	0.19	0.91	214	

8	0.22	1.04	244	

9	0.25	1.17	275	

10	0.28	1.30	305	

11	0.31	1.43	336	

12	0.33	1.56	367	

13	0.36	1.69	397	

14	0.39	1.82	428	

15	0.42	1.95	458	

16	0.44	2.08	489	

17	0.47	2.21	519	

18	0.50	2.34	550	

19	0.53	2.47	580	

20	0.56	2.60	611	

21	0.58	2.73	641	

22	0.61	2.86	672	

23	0.64	2.99	702	

24	0.67	3.12	733	

25	0.69	3.25	764	

26	0.72	3.38	794	

27	0.75	3.51	825	

28	0.78	3.64	855	

29	0.81	3.77	886	

30	0.83	3.90	916	

31	0.86	4.03	947	

32	0.89	4.16	977	

33	0.92	4.29	1008	

34	0.94	4.42	1038	

35	0.97	4.55	1069	

36	1.00	4.68	1100	96 Days

​

 

[DrDave]

Johnnie
What you have is normal loss due to evaporation. My pond loses about .75 inches a day and I know I don't have any holes in my liner.

I have had spas and swimming pools and they lose the same about. There is no way to stop it without sealing the top to avoid the evaporation.

In 96 days, are you saying that no one is there to top off your pond? If that is so, how are you going to feed them?

 

[Shdwdrgn]

Mine does that too, and I have pre-fab liners. Depending on the weather, I will lose anywhere from 1 to 4 inches of water in a week. The only thing that helps this is that during the Summer, my sprinkler system helps replace some of the water, so I may only have to top off every 2 or 3 weeks.

Keep in mind that features such as waterfalls and fountains will make this problem even worse. I would assume you turn off your fountain during the Winter months, so that should help, but conversely, the air is drier and evaporation can be higher.

 

[carolinaguy]

with all due respect i don't buy 3/4 inch water loss as normal evaporation in a pond. mine is 4000 gallons and 3/4 inch represents about 35 gallons of water in my pond i think. i never see a drop like that unless there is a leak. 1/8 inch a day maybe due to evaporation, but probably not.

if there is a leak you can start from the top down to narrow the possibilities.

 

[addy1]

My pond does not lose that much either, I have to top off maybe once a week and then it is only down about an inch

 

[Shdwdrgn]

It depends greatly on how much surface area you have, too. My pond is made from the pre-fab liners, so its only 18" deep, therefore I have a very high ratio of surface area to volume, and thus tends to evaporate a lot quicker.

As for finding the leak in a liner... without pulling it up or seeing any obvious signs of where the leak is, I'm not really sure if its possible.

 

[addy1]

It depends greatly on how much surface area you have, too. My pond is made from the pre-fab liners, so its only 18" deep, therefore I have a very high ratio of surface area to volume, and thus tends to evaporate a lot quicker.

As for finding the leak in a liner... without pulling it up or seeing any obvious signs of where the leak is, I'm not really sure if its possible.

My pond is 27x20feet or so, even dead of summer it did not drop very much. Once we filled the bog the water did decrease faster, the pea gravel has a lot of surface area that allowed for increased evaporation.

He could not refill until the water slows down in it's level dropping, that would let him know what level the leak might be at. Then it would be a search at that level for the leak.

 

[DrDave]

Wind, temperature, movement and surface area all contribute to the loss.

 

[rdk]

My pond drops a lot of water also, and with my float switch in play its a problem. I too was upset about a leek that I just can not find. RDK

 

[pondbuilder13]

You can look for like mud or silt coming up or turn off your pump and look and see if the silt is flowing and building up at a certain spot

 

[DrDave]

If you truly believe you have a leak, here is how you find it in a liner.
1. Let it leak until you think it has stopped.
2. inspect the water line for obvious holes or tears.
3. Use an eyedropper and milk to carefully go around the suspect areas. The leak will draw the milk into it.

If the pond continues to go down, then check your waterfall, that is the number 1 culprit and the most likely suspect since liners almost never get holes in them.

My stream gets so much plant growth from the Hyssop that it directs water over the liner if I don't trim it back.

 

[WolfStock]

Wind, temperature, movement and surface area all contribute to the loss.

Yes. I've noticed a big difference in evaporation on warm and sunny days vs. cooler cloudy days.

In my case I have a fall, so get a lot of loss from more surface area and some splashing. In my case I lose probably anywhere from 0.5 - 3.0 inches a day, depending on the weather. (I have a really small 50-gal pond, so losing a few inches isn't a big burden on the water bill)

If you're really concerned about it - you should probably keep track of how much is lost each day along with the weather conditions for that day.

 

[Johnnie]

Guys, thanks for all your inputs and suggestions. Meanwhile I'll just keep on refilling the pond until I find some time to fix the leaking problem. Here's today's video of my pond after I refilled it. Hey my lotuses went on a Merry-Round-and-Round-Ride on the pond

[ame]

 

[ponderpaul]

My liner has no penetrations. I have 4 falls from 2” to 10”, the 2 larger ones produce some splash. I would be very happy with only 3/16” per day.

 

[carolinaguy]

here's a thought. the standard for changing and replacing pond water, this is not evaporation but actual water removal, is a minimum of 10 percent of the total volume per week. the idea, which you probably already know, is to remove dissolved organic compounds (DOCs) which lowers the nitrate level, to dilute toxic compounds, reduce the parasite population, lower nitrites, and generally to approximate a natural open pond in which the fish never swims in the same water twice. as an example, we like to change out water at about a 25 percent rate per week out of personal opinion.

so if your leak doesn't cause landscaping problems and you can't see the water pooling anywhere and if the rate is below 10 percent per week, why worry about it? in that case you really don't have a leak; you have an unplanned but useful automatic drain that helps you with your change out schedule, and the water is probably watering some vegetation in your yard somewhere.