Critique My First Pond Plans


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Hello pond people, this is my first post here so I hope you'll bear with me if I sound naive.

I'm in the process of building my first pond at my home in the UK and would greatly appreciate feedback regarding the design of the filtration/ aeration system. I believe the actual pond vessel will be adequate for my needs, but I would very much appreciate some advice if I've missed the mark.

It will be a simple, straight sided pond dug 76 cm (2ft 6in) into the ground with a further 61cm (2ft) of water above ground, contained within a thick wooden frame. The volume of water will be approximately 2727 litres. I hope to keep six goldfish.

My biggest concern is this: Is a container bog filter suitable bearing in mind the Great British weather? In other words, will the bacteria and plant life survive the winter and provide adequate filtration?

Assuming the previous question is answered in the affirmative, here's how I intend to proceed:

A 1200 litres per hour pump connected to a 300 litre tank (something similar to the common blue type) in which to build an upflow bog filter. Various grades of granite rocks, stones, pebbles and gravel (largest at the bottom etc) will fill the container, with a void space of 10cm at the bottom. The piping will be similar to that recommended in the Ozponds YouTube video: https://www.google.com/url?sa=t&sou...xa8BegQICxAF&usg=AOvVaw2HfAnE1g08YcbZ-TaSoeNu

Do let me know either way what you think, many thanks indeed!
 
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brokensword

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Hello pond people, this is my first post here so I hope you'll bear with me if I sound naive.

I'm in the process of building my first pond at my home in the UK and would greatly appreciate feedback regarding the design of the filtration/ aeration system. I believe the actual pond vessel will be adequate for my needs, but I would very much appreciate some advice if I've missed the mark.

It will be a simple, straight sided pond dug 76 cm (2ft 6in) into the ground with a further 61cm (2ft) of water above ground, contained within a thick wooden frame. The volume of water will be approximately 2727 litres. I hope to keep six goldfish.

My biggest concern is this: Is a container bog filter suitable bearing in mind the Great British weather? In other words, will the bacteria and plant life survive the winter and provide adequate filtration?

Assuming the previous question is answered in the affirmative, here's how I intend to proceed:

A 1200 litres per hour pump connected to a 300 litre tank (something similar to the common blue type) in which to build an upflow bog filter. Various grades of granite rocks, stones, pebbles and gravel (largest at the bottom etc) will fill the container, with a void space of 10cm at the bottom. The piping will be similar to that recommended in the Ozponds YouTube video: https://www.google.com/url?sa=t&source=web&rct=j&url=https://m.youtube.com/watch?v=zvoOCq3gcTc&ved=2ahUKEwiUquu00vryAhUQYsAKHfi1Bg0Qxa8BegQICxAF&usg=AOvVaw2HfAnE1g08YcbZ-TaSoeNu

Do let me know either way what you think, many thanks indeed!
Sorry everyone seems to have missed this post; I'll try to clarify some of your questions.

A bog should work fine for your weather; in the winter, when the fish slow down, so too does the bacteria. Not all dies but most does, but your water won't need their services during the winter season. In the spring, it'll ramp back up as temps rise and food sources multiply.

Don't use any sharp edged stone in your bog--just round stone (river stone) as the sharp stuff will eventually lock tight and you'll not get the benefit of open spaces for the water to flow up. Too, the sharp stone may cut your bog liner.

Careful on your wooden-above-ground frame; watch some videos of other folks doing the same so you get the right size wood and construct it in a such a way that the sides don't bow out.

Try to make your bog 30% by volume of your pond, but it'll still work even if you come up a bit short.

Hope this helps!
 
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The challanges will be if the pond is too small that your pond may freeze solid in the winter. And the bog and pond do go into a hybernation sortta speek and the key is to have the water have a area that never freezes from air exchanging and not letting the bog dry out you meet those requirements you should be fine
 

addy1

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Welcome to the forum!

Try to make it as large as you can, bigger is better with ponds, they are more stable.
How cold do you get?

Agree with above, make sure your bog does not go dry in the winter. I shut mine off and it retains the water so the plants never dry out.
 
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Thank you all for your replies. The pond will be 1.2 m deep by 1.2 m by 2.4 m, so in theory ought to be 3456 litres (minus any stones/ gravel etc.)
I've revaluated the bog filter and think that a 400 litre tank would be better, with a combination of smooth stones, pebbles and maybe Alpha Grog towards the top.

We don't get much below - 1 centigrade in Gloucestershire, on average, but I've got myself an aeration stone system to keep things oxygenated and moving. I'll have half the water content below ground and the other half above.

I now intend to use 6 inch thick blocks to make the pond structure above ground, as the cost of wood is unbelievably high at present and I can't seem to source hard wood, meaning the lifespan of the wooden frame would be reduced.

My main worry is that the bog filter tank isn't going to be big/ efficient enough.
I intend to gravel the bottom of the pond and use stones etc alongside oxygenating plants to improve water quality.

Now that things have evolved, I wonder what you chaps and chappettes think of things so far?
 
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I
Sorry everyone seems to have missed this post; I'll try to clarify some of your questions.

A bog should work fine for your weather; in the winter, when the fish slow down, so too does the bacteria. Not all dies but most does, but your water won't need their services during the winter season. In the spring, it'll ramp back up as temps rise and food sources multiply.

Don't use any sharp edged stone in your bog--just round stone (river stone) as the sharp stuff will eventually lock tight and you'll not get the benefit of open spaces for the water to flow up. Too, the sharp stone may cut your bog liner.

Careful on your wooden-above-ground frame; watch some videos of other folks doing the same so you get the right size wood and construct it in a such a way that the sides don't bow out.

Try to make your bog 30% by volume of your pond, but it'll still work even if you come up a bit short.

Hope this helps!
I think the pond will be 3000 upon reflection (earlier I was citing outside measurements). Would a 650 litre tank for my bog filter manage a pond of 5 fish do you think?
 
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brokensword

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I I think the pond will be 3000 upon reflection (earlier I was citing outside measurements). Would a 650 litre tank for my bog filter manage a pond of 5 fish do you think

so 750 gallons vs 150; that's about 20%. As noted, you'll still get a lot of benefit, so go for it. Goldfish don't require the same filtration as koi, so that helps you. Also, they don't need to be fed nearly as much, i.e. don't overfeed and you'll get even more benefit. And worst case scenario, you can either upgrade the tub to something larger or just add an additional one.
 
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so 750 gallons vs 150; that's about 20%. As noted, you'll still get a lot of benefit, so go for it. Goldfish don't require the same filtration as koi, so that helps you. Also, they don't need to be fed nearly as much, i.e. don't overfeed and you'll get even more benefit. And worst case scenario, you can either upgrade the tub to something larger or just add an additional one.
Sorry to sound dense but where did you get those numbers from?

My pond will be roughly 3000 litres (659 gallons) and I'm aiming for pretty much crystal clear water.

Bearing in mind I've seen bog filters of 10-15 % the pond volume achieve this on YouTube, albeit in Australia, I am concerned about the disparity in opinion.
 

brokensword

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I was rounding as a liter is about 1/4 of a gallon, yes? So, rough math.

As I said, you WILL benefit and it's not a hard and fast rule (30%); I don't have that much but my pond is enclosed and I ran out of room. Still, if you look at my vids, you'll see the water is clear enough to see across 18', underwater and certainly, down to 44" from the patio side. I've never had green water; never. Just make your bog and let it work; you can always add another or increase the depth/height of the one you have now. You can also put a thin layer of pea gravel on the bottom of your pond to give even more surface area for the good bacteria to colonize. The plants in your bog are mainly taking out nitrates, just like any floating plants can and will do, so it's not like you don't have further options.

The disparity is probably based on anecdotal evidence; they may be understocked and thus 15% volume would work. They may never feed their fish and may not even need that much. I have over 35 medium koi and over 100 gf and most here will say I'm vastly overstocked. Still, EIGHTEEN feet of visual clarity, you know? And all I filter with is the bog. Well, I actually also have a sock prefilter to help keep the bog from clogging, but that's mechanical, barely any bio going on there.
 
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I was rounding as a liter is about 1/4 of a gallon, yes? So, rough math.

As I said, you WILL benefit and it's not a hard and fast rule (30%); I don't have that much but my pond is enclosed and I ran out of room. Still, if you look at my vids, you'll see the water is clear enough to see across 18', underwater and certainly, down to 44" from the patio side. I've never had green water; never. Just make your bog and let it work; you can always add another or increase the depth/height of the one you have now. You can also put a thin layer of pea gravel on the bottom of your pond to give even more surface area for the good bacteria to colonize. The plants in your bog are mainly taking out nitrates, just like any floating plants can and will do, so it's not like you don't have further options.

The disparity is probably based on anecdotal evidence; they may be understocked and thus 15% volume would work. They may never feed their fish and may not even need that much. I have over 35 medium koi and over 100 gf and most here will say I'm vastly overstocked. Still, EIGHTEEN feet of visual clarity, you know? And all I filter with is the bog. Well, I actually also have a sock prefilter to help keep the bog from clogging, but that's mechanical, barely any bio going on there.
Oh I see! Sorry about that, I've been wracking my non-mathematical brain over this for quite a while in an attempt to be as accurate as possible.

With all those fish I must say that these bio filters are far less fragile, if that makes sense, than I thought.

Thanks for taking the time to explain, it's fascinating and useful to get all these different perspectives.
 
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addy1

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I built mine with no sizing, no % just dug the pond then dug the bog. My bog did end up being huge and it works great.
I did a lot of reading about monster ponds, filtering with bogs, way back in 09 so decided that was going to be my build. It works.

Any bog type filter helps even if not 30%
 
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