leaking pond

[Duncan]

hi there

i still have my hospital pond set up in my summer house, its 9ft x 3ft x 3ft 475 gallon its a nice butal liner!

right i was going to go to Kens and get some small koi to start up again till i can build the bigger pond, thing is its just decided to start leaking in two weeks its lost 2/3rds its depth but i cant see where its going? there is no evidence of it leaking other than the level going down!

right the water gravities out at half the water depth through the wall with a 2" socket and down pipe to the pond bottom, so i figured about a week ago it was leaking on the flange but its gone down lower than that now!

so unless somebody has got any other ideas my next plan is to see where the water level is when it stops then get in with a torch and see if there are any marks on the waterline? sound about right?

but what if it goes right down to the floor?

bloody fish hey!

[DaveB]

Duncan Sounds like you have a plan. We always need a plan. Sorry if I can,t help more than sympathise with you. At least if the water goes down to the bottom the chances are that it will be the bottom drain flange.
I have leak on my pond, have done for a few years but can still maintain overflow when trickle in 24/7. However these things tend to get worse over time. best of luck with this one. Best REgards Dave

[Manky Sanke]

Duncan,

A couple of questions, is this an above ground pond in your summer house? Does it have a bottom drain or does the pipe going down from the 2" flange act as a deep suction point?

[Duncan]

hi Syd

sadly its lost another 2 or 3 inches

yes Syd the whole pond is above ground and no it has no bottom drain, the 2" pipe flange half way up into the settlement chamber has an elbow and a length of pipe going down to the bottom that acts like a bottom drain but i have swing that up so the end is now well above the water line in fact the top of the pond wall as well

just have to see where this thing bottoms out

dunc

[Duncan]

looked in the pond today, there is about 7-8 " of water left, in the lowest corner there were fresh earth worms wriggling, so im guessing they have travelled upstream from the leak and through the breach,, dunc

[Manky Sanke]

Duncan,

I guess you will already have figured out the various possibilities but, since this has always been and educational forum, I'll post them anyway for the benefit of people who like to look in and learn.

From your earlier description I was guessing that this was an above ground pond with the pipe from the flange going down to the bottom and acting as a deep suction point.

One possibility I thought of was that water might have been syphoning out through this pipe to a leak outside the pond and that the liner might have been intact. From what I imagine might be your layout this probably would have been obvious due to a wet patch on the summer house floor but, for anyone else with a similar problem on an outdoor setup, syphoning out to an external leak might not have been so obvious. You've done the obvious thing of swinging the pipe up out of the water so that could be ruled out.

Being an above ground pond, ground water level isn't an issue but, with an inground or partially inground pond, the level of water outside the liner might confuse the issue of finding a leak. If there is a hole in a liner, (or bad seal around a fitting etc.), then water will leak out by gravity and stop when it just goes below the hole so one way to find the leak is to wait until the level stops dropping, then the hole will easy to find by looking around the surface. That might be thought of as a statement of the blindingly obvious, but there is an important condition - the water leaking out through the hole must be able to get away.

If the structure that contains the liner is reasonably waterproof or there is a significant level of ground water outside the liner then, even if the leak is right at the bottom, the level of water inside the liner can't fall below the level of water outside it. Water pressure inside a non- leaking liner holds it tightly against the walls of a structure or the ground outside it but where there is a leaky liner and there is also water outside it then this changes.

As the slowly falling water level inside the liner reaches the water level outside it, the pressures begin to equalise and so there is nothing pressing the liner against the walls or outside ground. The liner will move away from the wall and, if you press against it, instead of it feeling tight, it will feel "squidgy" or it may even float away from the wall entirely.

At this point, the simple strategy of waiting for the water level to fall as far as the hole won't work. In my field, swimming pools, where there is a leaking liner coupled with either a ground water problem or the pool structure holding water and preventing the water level from dropping as far as the hole, there are various options such as draining the ground or the pool shell. There is even a nifty piece of equipment that can be hired that uses electronic currents in the water to point towards the hole just like a compass can be used to find a hidden magnet by always pointing towards it from several different directions if you set up a suitable search pattern.

Those techniques aren't cheap but they are used because of the sizes of liners and the volumes of water involved would make searching for an underwater hole near impossible plus the fact some customers want their pools back in action asap and are prepared to pay for whatever is necessary to speed up the process. Many will just have the liner completely replaced rather than wait while a leak is located. We poverty stricken koi keepers have to use less dramatic and cheaper methods.

If a leak in a pond is significant, and still dropping, we can remove the fish, turn off the equipment so that the water becomes still and try dropping an indicator dye into the water at strategic locations (i.e. near fittings or bottom drain seals) to see if the colours are drawn towards the leak. Possibilities are a FEW individual grains of potassium permanganate or malachite green crystals, (but don't allow them to settle onto the bottom and stay there for any length of time in case of damage to the liner). Drops of liquids, even milk, injected into the water via an eye dropper with a couple of feet of airline attached are another possibility.

The water must be still, only small amounts should be used at a time, and there is a degree of luck in these methods but they are worth trying.

Coming back to Duncan's case, or where all other methods fail, getting in and conducting a fingertip search is sometimes the only option.

Or have I missed any ideas?

[Duncan]

Syd

thats a great assessment and will im sure be of great use to anyone reading it

i looked tonight and im down to around 2" so this a fear is going to go down to the wire if thats the case i may yank it out and put a box welded liner in get rid of the folds in the corner, or i may get bob Hart up to glass it for me or do it myself i mean how hard can it be?

dunc

[Manky Sanke]

Thanks Duncan,

If anyone has any remaining questions about how to set about finding leaks on other types of ponds such as glass fibre finishes or ponds where the bottom drain or other pipework might be a possible problem, I'd be glad to help suggest a suitable procedure.

As for glassing your own pond, I've only glassed one pond myself and I didn't find it that hard. Obviously, although this is a relatively small pond, you will be working against the clock, getting the matting laid up, properly wetted and doing the fiddly bits but, as with any DIY job, proper preparation and thinking it through beforehand rather than trying to figure out what to do next while the resin is going off will be the key to success.

However, bearing in mind that I've done a total of one job, if you decide to do your own, then I'd follow Bob's advice because I've heard that he might have done a few more than that.

[Glenn]

Hi Duncan, get Bob up he is the man for glassing

[Bob Hart]

I'm still glassing Duncan!

Sounds like you cant keep away and want to start keeping Koi again!!!

If you want it glassed, you could put a bottom drain or side wall drain in before I do this?

[Duncan]

thanks Bob i may take you up on that i may extend the pond out a bit first so its 2 meters wide a meter deep and 3 meters long

many thanks again nice to see you on koiquest again

dunc

[maxinegrundy]

LOL .. anyone fancy a pond building party at Duncans ?
LOL no pressure Duncan ..

Come on guys ..how much help have we had over the years from Duncan ..i think its time we gave a little back.
Thats if Duncan doesnt mind us descending on him ..i am sure he wouldnt trun a few extra pairs of hands down.
Whos up for it ??
MAx

[Manky Sanke]

Count me in, I've learned so much from Duncan's health course and from his articles and posts on here that it would be great to have the opportunity to pay something back.

[Duncan]

thanks guys but im not sure what form this pond is going to take yet but i thank you all

i fofund the leak three puncture holes at the very lowest point of the pond caused off my sump pump for pumping out

ah well

dunc