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  1. #1

    Building it myself

    I have decided to build a new sleeper pond, I want to put a bottom drain in, it's only going to be a 500 gallon with a box liner, with the easypod air.
    I hope to build it on my existing patio area with out digging anything up.
    My question is can you get a 3" bottom drain? If so where is the best place to get one from.
    What do you think if I build the sleepers up then put 110mm kingspan insulation board in the bottom with the drain and pipe cut to size in it, then exit the pipe through the sleeper.
    Can anyone tell what is the depth of a 3" or 4" bottom drain? are they actually 3-4" in depth?
    It might be a daft idea.
    Or would a 2" bottom drain be best for this size of pond, would it pull the waste good enough.
    I want it gravity fed into a easypod air.


    Last edited by Airbourne; 16-01-2025 at 04:25 PM.

  2. #2
    Senior Member Rank = Supreme Champion RS2OOO's Avatar
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    3" bottom drains are readily available, I just did a quick google search and a handful came up. I couldn't tell you which one is best, I would expect all to be more than capable of doing the job.

    You could exit the pipe through the sleeper, but the drain itself would need to be very well supported so as not to rip through the liner. I think digging a trench and concreting the drain and pipe in would end up being the simpler option.

    A 3" drain probably is about 4" in depth, but I've never measured one.

    Consider a 4" drain if you think there might ever be a possiblity of extending the pond at a later date.

    Unless you have plans that don't include Koi, 500 gallons is very small. Even just 3 small koi will outgrow it within a year and you may eventually need to re-home them. My first sleeper pond was 1600 gallons and I had 8 tiny Koi. A year later some of the Koi were over 50cm and I had to extend it to 2500 gallons.

    Here's the build thread of my first sleeper pond which may or may not be of help to you, but you're welcome to check it out:

    https://www.koiforum.uk/pond-constru...ond-build.html

  3. #3
    I have read your post 2018, you worked hard on your first build and had a few challenges along the way, it looked smart when you finally got it finished.
    I am getting to old for digging now, plus I had a stroke in 2022 so it's slowed me down a bit, but I am one of the lucky ones.

    I was going to buy a EZ pond 500i, but I can build a raised pond a lot cheaper and yes could go a bit bigger.

    I have a smaller raised pond now about 200 gallons, but it runs off a pressure filter and it's a lot of work keeping the filter clean.

    I have brought easypod air and was going to run it pump fed, but after watching alot on youtube about gravity fed, that would be a better way to go, but have also thought about retro bottom drain, but can these run on gravity fed?

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  5. #4
    Senior Member Rank = Supreme Champion RS2OOO's Avatar
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    A retro bottom drain would work, but if digging is an absolute no-go, then your first idea to have it coming through the side of the bottom sleeper might still be preferable and is probably achievable.

    I've not thought this through but maybe you could lay a membrane on the patio, then fit the insulation and then pour cement around the bottom drain to hold it in pplace before building up from there. Once the entire base and insulation is set out, fill any remaining gaps with soft sand.

    Someone might be able to suggest better options, or possibly I'm over engineering it, but once the bottom drain is in you don't ever want to be having to empty the pond to deal with any issues that develop.

    Obviously being an above ground pond, insulation will be important all round.

  6. #5
    I know they lay a menbrain down like kingspan on a floor and pour concrete over that when building a house and that helps to insulate it.
    My idea was to put concrete slabs on top of the patio no cementing involved, then build the sleepers on top of them, so in theory if you put 6 2x2" you could have a pond size of 6x4 and so on, in that way it would raise the sleepers off the patio and rejuice the chance of the sleepers rotting.
    I would then put a sheet of kingspan 110mm thick inside and cut it to the size of the bottom drain, I might have to compact it with something like self leveling cement to fill in any voids.
    My only concern is would the weight of the water crush the kingspan and the bottom drain?
    I know you can buy a fibreglass pond all ready built and they recommend sitting them on kingspan so not to cause any damage.
    Any views would be welcome

  7. #6
    Senior Member Rank = Supreme Champion RS2OOO's Avatar
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    Someone else can hopefully advise how the kingspan copes with crush forces, I've never used it for a base but I know many people do and I've never heard of issues being reported about it crushing under the weight.

    When you consider your body is 80% water and you can walk on kingspan without it crushing, I would expect it should easily manage a pond full of water, but best to get confirmation from someone who's done it.

    Alternatively you could just fill the base with sand and only insulate the sides. Sand is an effective insulator.
    Last edited by RS2OOO; 17-01-2025 at 02:49 PM.

  8. #7
    Yeah that might be another way of doing it, never thought about using sand 🤔 👍 that could be a better solution, if I do it that way I would line the bottom first with a plastic membrane to keep the sand from falling into any crakes.
    Cheers for that

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  10. #8
    Junior Member Rank = Fry GDL's Avatar
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    The problem with Kingspan and similar is that it degrades over time in damp environments, whereas expanded polystyrene does not.

  11. #9
    Senior Member Rank = Adult Champion Alburglar's Avatar
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    Dunno about expanded polystyrene. It doesn't biodegrade as such, but it does breakdown, basically to a dust of micro plastics.

    Normal polystyrene Doesn't normally mix well with fiberglass. Google says the expanded stuff is alright if you use epoxy. (Expensive)
    ...but if using a liner perhaps the other stuff would workout cheaper?

    polyurethane foam sheets is the norm for lining ponds that are being fiberglassed.

    ... basically anything like that will brake down eventually beneath the liner if it's damp, but it will just sit there like sand would. It will still be doing its job.
    Last edited by Alburglar; 18-01-2025 at 08:45 PM.
    2660 Gallons. 4" Bottom Drain and Skimmer. Draco Solum 16 Drum. Anoxic Filtration. Air lift returns.

  12. #10
    Junior Member Rank = Fry GDL's Avatar
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    I agree. If you are glassing over it, then its fine.
    If you are putting it on the ground to act as a base then it will degrade. Most polyurethane foams are not UV stable either, which hastens the degradation if exposed to sunlight.

    Laid on the ground as a base then expanded polystyrene will last much longer than polyurethane.

  13. #11
    Yeah that's what I was thinking, would it degrade over time, so the best way is use sand, what RS2000 suggested.
    So what would be best to line the sides with, when using a pond liner?
    Last edited by Airbourne; 18-01-2025 at 10:29 PM.

  14. #12
    A small pond which is completely above ground, however well insulated, will tend to suffer from relatively rapid temperature fluctuations and in prolonged cold snaps definitely need some form of heating to prevent dangerously low water temperatures.
    My DIY ponds from 1988 until present day.
    All can be found here:
    https://www.ukzero.com/pond.htm

  15. #13
    Been looking at the retro 4" bottom drain gravity fed.
    Has you know I was thinking about bedding the BD in kingspan or in sand, but do you think a retro 4" BD in 3" pipe would work has effectively?

  16. #14
    Senior Member Rank = Supreme Champion RS2OOO's Avatar
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    Quote Originally Posted by Airbourne View Post
    Yeah that's what I was thinking, would it degrade over time, so the best way is use sand, what RS2000 suggested.
    So what would be best to line the sides with, when using a pond liner?

    I'd still stick with kingspan for the sides.

    The pond is small, the liner is flexible, I don't think there will be any issues.

    Part of my sleeper footings cracked and moved outwards 3/4" at a water depth of around 18" which stretched the 1mm EPDM liner by that amount across the width of the pond and it didn't split.

    Maybe run a bead of silicon in the gaps between the sleepers to prevent water ingress from the sides, and use decking around the top of the pond as coping, overhanging the edge of the pond by 3/4" to prevent water running down the sides of the sleepers.

  17. #15
    Yeah I will still use kingspan on the walls.
    I intend building it 8' x 6' x 1 metre deep might even go a bit bigger yet.
    I am trying to find out if the 4" retro BD dome gravity fed, by eco filtration works but I'm struggling to find any info, so if anyone is using one I would be grateful of any info.

 

 

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