Thread: New pond build - First pond!

The soak away was filled with gravel in sturdy supermarket veg plastic crates (great deal from Solent Plastic’s eBay shop!) and will have the membrane folded over the top and zip tied to the pipes coming in.



Jumping around in terms of order, but before the beds were filled, I ran all of the wiring for the outside lights so the beds could be planted. I have down lighters for the patio area and spike lights to illuminate the tree ferns from underneath.


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The pond hole was then dug. I was aiming for 4.5m x 3m roughly with an ideal depth of 1.3m ish. It isn’t far off at 3.9m x 2.7m and around 1350mm depth. I hadn’t set myself strict size limits as I wanted to eyeball it so the size was proportional with the beds and what will be the patio area.


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Next I raked the bottom roughly level and started the laborious process of getting the MOT in. The machine had gone off hire by now so it was all by hand. I hate shovelling MOT!!



With the MOT in, I was playing around with BD placement.



I have a bunch of concrete sections that supported an old and throughly rotten greenhouse so that’s now gone and the concrete is for rebar stand-off.

I concreted in the bottom drains yesterday in roughly the position of the last picture. They are piped to roughly final height now and today I want to get some concrete around the swept bends to stop them moving when the base is poured on Tuesday.

Later in the week, the builder is starting the block work. I’ve got to get on the phone on Monday and order the window…..but I’m excited to see it start coming above ground in the next week!


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All of the pipe work is in pressure. The BD’s are all 4” and the skimmer is a 3”. I have the pressure pipe for the airlifts too. I have already run a 110mm soil pipe (above ground) so I can have a T from the BD drains as soon as they come up out of the ground so I can purge them.

I’ve been arguing with myself over boxweld liner vs fibreglass since the fist thought I had. The thought of that much fibreglass gives me a headache and I’ve never been convinced about glassing into BD’s - please don’t jump on that, I know a lot of folks do it and have no issues and I’m happy about that, but it isn’t for me. So a bloody big box weld is probably where I’ll go. Incidentally, I understand about the water pressure working in your favour for glass in BD’s (very well actually, I’m a mechanical engineer by trade).

Don’t know what else I can tell you at the moment…..I’m excited and looking forward to seeing some fish in it! In terms of fish, the main pond will be koi with a couple of Stellate Sturgeon.


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Got the bottom drains concreted in on Saturday ready for the concrete pour tomorrow. The rebar turned up at last so will be the builders first job in the morning.

I managed to use up the last of my concrete building up and over the swept bends where they turn vertically, so I’m hoping between that, filling them with water and stacking a few bricks on top the bottom drains won’t float away or move as they are bang on level and at at the same height.

For the civil engineers amongst us, I ran out of rebar lengths so to tie the pads for the bottom drains to the main pad I used what I had on hand….which was threaded bar and square washers should do a good enough job of holding it all together. Probably would have been fine anyway. But I can’t help but mess and reinvent the wheel.

There’s 4 cube of concrete being pumped in tomorrow and will give about 315mm depth. There’s also 600 dense blocks and 3t sand arriving in the afternoon and 20 bags of cement. The blocks are going broadside all the way up. I plan on pouring concrete between the outside wall and the edge of the hole when I pour the pads for my workshop and shed/pump room. That will give it a ring of concrete right down to the full depth. If there’s a nuclear apocalypse, I’m draining the pond and putting a roof on it, I think it’s one of the strongest structures around!

The (admittedly mechanical) engineer in me can’t help but think this is all massive overkill for a garden pond. On the other hand, better to do it right once than badly twice. And if I spend years nurturing tadpole koi to giants, I’d be gutted if the pond failed.

I’ll get some pictures of the pour if I can tomorrow and post.


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Update on the window situation. I’d talked myself into a framed window, but the lead time is 5 weeks and I’m not sure I want to wait. I had thought the place I use might build them to order, but I hadn’t anticipated 5 weeks! I’m currently toying with the idea of a frameless infinity window set into the block work, which is significantly cheaper. I’m thinking 2m x 0.6m x 31.5mm heat soaked toughened jobby. Cotswold Koi has them advertised straight from the manufacturer. I’ve read on here about people eating Tuff-X too, so I’ll give them a call tomorrow. Have to bribe my cousin to come and give me a lift with it as it will be bloody heavy!

I’ll sound the builder out tomorrow about cutting the internal reveal for me when he does the blocks so it’s easier. I’ll let you know the progress….

Morning of the concrete pour and my fish tank filter just started making a god awful noise and stopped pumping. Going to have to look at that now before the bacteria all start to curl their toes! When it rains it pours….

Got to tape the BD’s up and fill with water then fit the rebar then should be good for a pour at 12:00hrs.

I went with 3 BD’s for overkill but I’ve read a lot of people on here saying they wished they’d done more, so hope it isn’t going to cause me any piping problems later on!


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Rebar is in and ready for the pour later on today. We had a long chat about rebar over the BD pipes bs no rebar. In the end we decided to rebar it because it’s such a thin layer of concrete. We plan to get as much as we can over the top and with it being well packed underneath (when we pour) and filled with water we are hoping it will be strong enough. In hindsight, maybe I should have depot a 90 on the 4” coming out of the BD and dropped it 300mm. That would have necessitated a normal 90 though as two swept would have made it really deep. All the 90 are swept for the BD’s as I don’t want to restrict flow.

I’ve seen a lot of others BD set up like these though, so I’m hoping it won’t be an issue. With it being a box weld too it doesn’t have the sensitivity to movement that fibreglass would have. Fingers crossed!!!!


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Blocks, sand and cement (1st load) are here and ready to be carted around the back. Second load is due this afternoon after the concrete pour, so I’m thinking they can stay on the drive until tomorrow as everyone will be plenty sore by then.

Will post some pouting pictures later. If anyone is reading these, wish me luck!!


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Well that’s nearly 4 cube of concrete in. Nerve wracking process! The lads are floating it now, I’ll post some more pictures when it is floated the BD’s stayed put (though got buried for a while, glad I had them gaffa taped up). Relatively little drama all told. Hope the rest of the build goes that way!


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Well it’s all done, floated and starting to cure. There was maybe 8mm too much depth so the BD’s had to be trowelled around but there will be enough give in the liner for that. I’m praying the 1” air pipes are ok. The lads didn’t know where they were treading when they were sorting it out so I’m hoping at least 2 of the air feeds have survived…..


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The guys have certainly got the sunshine for the block laying. They are hoping to get a few layers down today but don’t want to go too high as the concrete has barely been down 24 hours now. The lion share of the blocks will go down tomorrow and finish the blocks on Friday.

Decided to go with a frameless window so will get on the phone today to see about getting that sorted. Will keep you posted


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Originally Posted by g mac

looking good Tom

Thanks! The lads are fair flying along.


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They’ve flown today. The finished level is about 12” down from the piece of wood you can see in the second pic. They would have done another 4 courses today if the concrete had had longer to cure but they knocked it on the head where you see it now and tidied up and will move on tomorrow.

Should start to get an idea of the overall look tomorrow as the window hole will take shape and the returns will start to be bedded in when they get towards the top. With them being airlift returns, they are at roughly water level, give or take.


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Originally Posted by Twhitenosugar

Looking good!

Great progress and it looks like you have really done your home work on getting it right first time around.

Good to see another air lift convert. They really are an efficient way to pump water in a gravity set up.

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Thanks!

Regarding the airlift, I was looking at pump power consumption and even with my solar panels, couldn’t justify the cost in summer. If I was lucky with the solar panels and got high quality pumps - which I would have done - it would have broken even at best with the summer, which makes the pond a heavy investment as it would also really include the solar…..

So airlifts it was. There’s some truly shocking flow rate calculations out there on the net, so I’m really unsure what the final flow will be. Some of the calculations I saw had no compensator for pope diameter or bubble size, which will be two of the biggest factors (after lift height) that determine flow rate. So, suck it and see I think! Should be plenty.

With the flowfriend on the skimmer and the cheaply Chinese vario’s on the lily pond moving it all around, there should be plenty of movement and turnover.

If anyone does have a set of those expensive flow meters that sit on the pipe and wants to pop over when done and tell me what flow I achieved they’d be more than welcome. Failing that, I’ll see about getting a cheap water velocity meter and calculate the approximate throughput.


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