Garden Pond construction

[Blackrat]

Having had a pond with a butyl liner spring a leak somewhere, I am now considering a preformed pond liner.
I'm after one about 2x3 metres. I cant really afford the best type, a glass fibre one, as they are about �600 -700+.
Anyone with any advice re polythene types such as Lotus / Blagdons, they are guaranteed for 20 years plus apparently.
TIA

[hammerman]

Firstly, liners don't usually "spring a leak" ....there must be a reason why (poor initial construction, stood on something sharp whilst doing maintenance etc). You need to find out how you got the leak.

Personally, i'd stick with the liner. I'd remove the old one, re-do the sand / carpet / underlay layer underneath, clean the old liner off and put it back in the hole roughly the way it came out and then fit a new liner on top. You can get butyl tape which will give a permenant repair too.

I use a firestone rubber liner on my 3,000 gallon koi pond and it's been superb.

[landscaper2]

First of all - dont panic!! Stating the obvious, the leak will be at the level the water stabilizes, so it shouldn't be too difficult to find. When you do, as Hammerman says, there may be a sharp object causing the problem. The repair process mentioned is very effective providing you follow the instructions. Are you running a waterfall? Getting a seal with a butyl liner can be dificult. We tape an extension liner to the maun liner and run this under any raised watercourse. Turn the pump off and re-fill the pond - see what happens. A weekend of investigation could save you hundreds of pounds and a lot of hard work. It's worth a go!