Replacing pond liner

[tom00_uk]

drop the level a bit below the level it falls to having first marked it and then run your eyes/fingers round till found, patch repair kits are available

[John Robinson]

Thank you Bugly. I presume that there are non-toxic leak-trace dyes available that will not harm the fish; I shall make enquiries. It will not be possible to see any dye emerging from the pond, as it it surrounded by a low brick wall and paving, so I assume that I would be able to see dye on the surface moving towards the leak. I had also thought about placing some small twigs or something similar on the surface to see where they head. Obviously, this would have to wait for a perfectly still day.

Thank you, also, Kayleigh. Because no surrounding ground is visible, I'm afraid it will not be possible to do as you suggest. I have, though, seen repair kits in my local aquatics centre, and am assuming that the present liner is some form of rubber which can be patched by these kits.

And thanks to you too, Tom. I shall certainly have another go at a visual and tactile search around the edge. I'm sure there must be a crack or hole somewhere.

My wife has also made a very logical suggestion: that I insert a tube into the liner, seal it well, blow air into the space behind and watch for bubbles! This unusual idea may, in fact, work as the liner edge is sealed well in mortar between two courses of bricks, and I don't think there can be any other place for immediate escape of the air. Still, I think I will keep that as a last resort.

[Cowgirl]

Good luck John. I too have a pond that I think has a small leak at the top, trouble is it's 16' x 10' so it's going to be a long slog trying to figure where it is! Your fish should be fine. I've moved house several times & had to move a large tropical aquarium, same principle and I never lost a fish, more by luck than good judgement probably! The advice about temperature is a good one.

[animartco]

If it is leaking I wouldn't wait too long! I don't know how big the fish are but remember it's an inch of fish to around a square foot of surface area, even for a day or so. If you are using wheelie bins you might need to use airation. If you haven't a pump you can use, you can buy airstones from aqua centres.

[John Robinson]

Originally Posted by animartco

If it is leaking I wouldn't wait too long! I don't know how big the fish are but remember it's an inch of fish to around a square foot of surface area, even for a day or so. If you are using wheelie bins you might need to use airation. If you haven't a pump you can use, you can buy airstones from aqua centres.

Thanks for your advice, animartco.

I have decided to leave things until the weather improves ('global warming', eh?!). The level of water is, for now, stable, although I still can't find a hole. The surface area of the pond is virtually the same as when it was full, so I'm not too worried at present.

If I do need to remove the fish and put in a new liner, I expect to complete the changeover within a day or, at most, two. In the meantime, I'm hoping the fish would be OK in the bath and/or wheelie bin for that short time.

I am still hopeful, however, of finding the hole(s), in which case I shall not need to remove the fish at all, but patch the existing liner. My next step is to fill the pond by another couple of inches and drop some milk in around the edges. If the water is leaking out, and the hole(s) is an inch or two below the surface, I'm hoping that the milk will head towards it.

[dampflippers]

I'm sure I have heard of polystyrene beads being used to locate a leak- the theory being that they will drift towards the hole, but I think this would be a bad idea with fish as they are likely to eat them. I expect wind would affect this method too.

If you end up doing a complete reline, and you use wheely bins, buy some wheely bin liners to line them rather than having to scrub the bins out. Not scented ones, just plain clear ones if poss.

If you don't have loads of marginal plants, to help locate the leak, rub round with a soft clean cloth or sponge to clean the liner, then feel round with your fingers. You can buy sticky pond repair tape which has a peel off back, but I don't know how long lasting it is.

Good luck!

[nightshade]

Originally Posted by John Robinson

Sorry to resurrect this thread, but I now need further advice.

I had planned to put in a new liner next week, but have noticed that the water in the pond seems to be going down to the same level and then remaining there. I have been topping up every day or two, but have left it for several days now at the same level.

I assume that this may suggest a leak somewhere at the present water level, but I cannot find anything. If this is the case, and I can find the leak, obviously I may be able to do a repair. I think the present liner may be rubber - it feels like it - although I'm not sure.

My question is, how can I locate the leak? Is there some clever and effective way of doing this?

I found when the pond started to lose water that I had a couple of minor problems
The wind was blowing water beyond the butyl lined stones of a rill

The edge of the pond liner under some flagstones had collapsed letting water drain out until it reached a new level caused by the collapsed section

The pump filterbox had tilted slightly and as the time came to clean the coarse filters water was running out of the tilted box

If you are going to the expense of a new liner I would think hard about improvements; to depth and size or adding shallows etc. rather than regret it later

[John Robinson]

Thanks Dampflippers and Nightshade

Rather than use polystyrene beads, I have decided to try a few drops of milk - I think it should be safe for the fish if the amount used is small. I did recently try small bits of tinder but, as you said, they were either blown by the slightest breeze or did not move at all. I shall feel around the surface edge once more when the weather gets a bit warmer. Last time I did that my fingertips dropped off through frostbite! (No, they didn't really.)

The wheelie bin liners would be a good idea. Thanks.

As for water being blown over the edge of the liner, this is unlikely to be the case here as there is a good eight inches of vertical liner above the present (reduced) water level. Nor can it be anything to do with the filter, as this stands externally well above the water level.

I'm not sure, Nightshade, about improvements. The main part of the pond is over two feet deep and there are already shelves around most of the edge. As for length and width, I do not want to disturb the low brick wall which forms the periphery and, anyway, there isn't really much room to make the pond larger.

Ideally, I should like to leave everything just as it is. The size and conditions must be OK as four fish from two or three years ago have multiplied about tenfold, and they look quite happy!

Thanks, both. I am always very grateful for any advice.

[John Robinson]

Well, I'm pleased to say that I've found the leak, or my wife has with her beady little eyes. It had disguised itself as a drop of water, which is how I had missed it.

It is an oval-shaped hole, about one-eighth by three-eighths of an inch, not a crack or slit as I would have imagined. Anyway, I have now patched it and shall re-fill the pond tomorrow when it has cured. I'm glad for the fish's sakes that I didn't have to put in a new liner.

The thing that puzzles me is how a hole of this shape and size could have developed.

Thanks, everyone, for your advice.

[nightshade]

Do you have a Heron?