Will this homemade pond filter design work?


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I'm also a proponent of bog filtration.
You will not regret building a bog.
Crystal clear water, no cleaning of filter media, no UV lights necessary. Pretty much maintenance free.

Grow your plants directly in the bog gravel.

I share your concern about the possibility of a leak in any exterior plumbing. That's why all my plumbing is within the pond/bog. None of my plumbing is outside the liner.

I have black 1-1/2" flex PVC from my submersible pump to the 2" bog manifolds.

The bog is a bit higher than the pond.

The only exposed part of that flex PVC is where it goes over the wall between the pond and bog. I surrounded the exposed part with rocks to hide most of it.

 
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brokensword

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Okay, here is my adjusted design, making room for a large bog that also serves to create six 4" high waterfalls, and hopefully some interest effects with water rushing through the rocks in the stairway-like areas.

View attachment 135493
The vertical dimension is exaggerated in this illustration.

Orange = brick wall, with metal reinforcement
Grey = bog
Blue = water level in main pond

View attachment 135492

Basically the bog ends up taking up space within the pond itself. The pond liner is laid inside and the inner walls built on top of the pond liner, creating 5 chambers (the back large is one, then two smaller ones on each side). I'm not sure if that is feasible, as usually I put water in the pond liner immediately, otherwise the wind will take it away...it is big enough to completely cover someone's house.

The back elevated part is already on a hill, with this staircase-like design, the pond wall somewhat matches the incline of the slope of the group (in 40 ft it rises 20").

Unfortunately this design seems to nearly double the cost of the pond, between bricks, aquablocks, and probably 5-10 tons of rock needed.
I like the new design; very innovative. Should be neat to see the cascades. There might be a problem though; the water will probably not reach as high as the center portion of your bog and therefore, won't cascade there. Water will take the path of least resistance and that center part, and the couple steps down, are going to provide a lot of resistance. I believe most of your water will be forced onto the lowest two steps and in effect, you're going to lessen bog efficiency by a lot.

This is what I'd suggest; create a flat bog where all your water gets a chance to rise. Dig out a center portion where you KNOW the water will pool. Place a secondary, probably less powerful, pump there. You can camoflage this pump by making a rock roof, which you can tie into the same rocks I'd suggest you put as 'step edge' rocks for your design. This secondary pump then takes the risen water pooling in the middle and you direct it to a top 'fake bog' that lies on top of the rock bridge. You'll have to get a bit creative re camoflaging but I can see it as a definite plan. In essence, what you'rd doing is taking the filtered water, sending it up higher to where you have plants (just as you would in this 'pooling' center part down below) and then letting it fall to either side and step its way down.

It wouldn't take much to put some thin, probably no more than 5" rocks in front of your pump #2 and make it look like a part of your 'elevated' rock pile with plants on top. I can see this working just fine, then. The bog works as it should and you get your creative waterfall steps. I'd love to see the build pics of this if you do it. You will have to work out how much water can pour over the bog wall and that which you'll be pumping up to the wfall step formation. You could eliminate this if you wanted to use a tee on your main pump and direct water to this 'raised rock wall step wfall' and just let the bog water overpour into the pond.

As I noted, your step edges would look great if you edge each drop with natural stone and use the same for your middle raised rock/wfall pile.

A word re doubling your cost; this is what I'd do and I don't see the cost as being horrific.

When you dig, make your bog shelf the same 12" depth below pond surface level as I did. This means your circular pond has a half moon shelf that is higher than your pond bottom. Create the wood box as mentioned earlier so you have the height you need/want for your wfall steps. This box goes on the shelf you dug and rises up above your pond height.

When you put your liner in, you'll start at the back of your bog, wrap it down and in and back up your bog box. FRom there, you overlap the front box wall and then down into your pond proper. This keeps all your water in ONE place by one liner.

Do as I did and keep at least a 6" shelf of dirt in front of where your bog box will sit. This is so you can camoflage the bog-pond wall with whatever you want. If you want a thicker facia, make the shelf the size of whatever you choose. I only needed the 6" because I was stacking 4" ledge stone.

A word re the cost; I didn't use aquablox and wouldn't just because of the price. What I did was use large 8-10" stone as my first layer (creating something similar to aquablox, though with less obvious open space for settling), then a layer of 2" cobble, then the pea gravel. If you price the volume of stone you'd need for this, I think you'll see a big cost savings. And you only really need the 12" of pea gravel to make your bog work.

If you want something like a vault and cleanout stack, consider a heavy duty plastic garbage can at the lowest point. They run about 36" depth, which is how deep my bog is. I cut out holes in the bottom lower sides so water can enter and (important!) make sure the top is at least 8" above your pea gravel. This is so water will be forced to flow all through your gravel and not up the diy cleanout stack/vault. I put some flag iris in mine and they can easily be removed should I ever need to clean out the bog.

Many don't even need/want this cleanout, so you could ignore this suggestion/cost, too.

So you should not need a separate liner for this; just one large one.
You will need something to make the bog box; I used ground contact pt 4x4s.
To get your step effect, you'll need another pump of lesser power.
To save money, consider rocking your bog all the way like I did.
Other than that, everything else should be the same.

I'll attach a drawing to better illustrate what I'm suggesting;
Untitled-1.jpg
 

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The pond liner is laid inside and the inner walls built on top of the pond liner, creating 5 chambers (the back large is one, then two smaller ones on each side). I'm not sure if that is feasible, as usually I put water in the pond liner immediately, otherwise the wind will take it away...it is big enough to completely cover someone's house.
Interesting design, but this part confuses me. You're building a 30,000 gallon pond with the appropriate sized liner and you think the wind could blow it away? Have you ever checked the weight of an EPDM liner? And when you say "the inner walls built on top of the pond liner" what does that mean?
 
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I like the new design; very innovative. Should be neat to see the cascades. There might be a problem though; the water will probably not reach as high as the center portion of your bog and therefore, won't cascade there. Water will take the path of least resistance and that center part, and the couple steps down, are going to provide a lot of resistance. I believe most of your water will be forced onto the lowest two steps and in effect, you're going to lessen bog efficiency by a lot.
Will this addition of walls (marked in red) force the water into cascades?

Water is pumped from the main pond into the bottom of C. C is basically the bog, and A, B, D, and E probably can't function as true bogs, so they'll be filled 95% with dirt, a small plastic liner placed on top, then a shallow layer of river rocks for them to flow through.

pool3.JPG


The lowest red wall is 4" above water level, forming chamber A. Then chamber B has walls 4" higher than chamber A, though the walls marked in orange are slightly higher still, forcing the water to spill over the red wall.
 
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Interesting design, but this part confuses me. You're building a 30,000 gallon pond with the appropriate sized liner and you think the wind could blow it away? Have you ever checked the weight of an EPDM liner? And when you say "the inner walls built on top of the pond liner" what does that mean?
My meaning is, this pond has many inner walls:

pool3.JPG


First, I'd built the outer wall, then lay down the pond liner (50 ft x 50 ft). Then the seven inner walls are built on top of that pond liner. I don't know if pond liners are designed to have heavy weight applied on top of them like this.

Additionally, I usually put in a pond liner, then add water which helps me to shape it nicely. In this case, I'd be spending several days adding the interior bricks before I can add water to the liner, so I'm not sure if that will cause a problem with the shaping of the liner, the wind and weather, etc.
 

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My meaning is, this pond has many inner walls:

View attachment 135497

First, I'd built the outer wall, then lay down the pond liner (50 ft x 50 ft). Then the seven inner walls are built on top of that pond liner. I don't know if pond liners are designed to have heavy weight applied on top of them like this.

Additionally, I usually put in a pond liner, then add water which helps me to shape it nicely. In this case, I'd be spending several days adding the interior bricks before I can add water to the liner, so I'm not sure if that will cause a problem with the shaping of the liner, the wind and weather, etc.
Epdm is not light enough for the wind to blow it around, especially a 50’x50’, it probably weighs over 700lbs.

Yes the liner can handle heavy weight put on it, but I would use a layer of underlay down as usual first then the liner then another layer of underlay under your walls and bog over top of the liner. Also use the heavier 8oz non woven material the stuff is tough as nails. I wouldn’t take a chance of what you are using to build the walls cutting the liner by laying it directly on it.

Many of us on here have bogs with many feet of rock and gravel pushing down on the liner protected by underlay, as well as rocks that weigh 3000lbs or more.
 
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brokensword

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Will this addition of walls (marked in red) force the water into cascades?

Water is pumped from the main pond into the bottom of C. C is basically the bog, and A, B, D, and E probably can't function as true bogs, so they'll be filled 95% with dirt, a small plastic liner placed on top, then a shallow layer of river rocks for them to flow through.

View attachment 135496

The lowest red wall is 4" above water level, forming chamber A. Then chamber B has walls 4" higher than chamber A, though the walls marked in orange are slightly higher still, forcing the water to spill over the red wall.
if you eliminate A and B from being bogs, i.e. there is no way for water to get from C to them except via the surface of C, then yes, it will work as you wish. I'd not use dirt but rater, fill A and B with more pea gravel. This way, the water will flow through as in C, but sideways and give you at least some bog like action. Also, your plants will be more functional as the only ingredients they'll get is pond water and not some from the dirt.
 

brokensword

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My meaning is, this pond has many inner walls:

View attachment 135497

First, I'd built the outer wall, then lay down the pond liner (50 ft x 50 ft). Then the seven inner walls are built on top of that pond liner. I don't know if pond liners are designed to have heavy weight applied on top of them like this.

Additionally, I usually put in a pond liner, then add water which helps me to shape it nicely. In this case, I'd be spending several days adding the interior bricks before I can add water to the liner, so I'm not sure if that will cause a problem with the shaping of the liner, the wind and weather, etc.
agree with jhn; I'd not put anything with sharp edges against my main liner. That's why I suggested you build your walls and cover over with one piece liner. Plus, the cost is going to go up if you use a lot of brick. Not that it can't be done but you'd probably have to lay more liner (extra pieces) under your brick and on top of your pond liner to make it more secure. Your above bog structure can all be made from 4x4s and used by one liner; just have to consider how to camouflage the face of the bog--that's why I suggested the shelf in front of the bog structure.
 
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I'd suggest the same - build your structure and then use one piece of liner to cover the whole thing. It would not be fun to build that whole thing and then realize you MIGHT have created a tear under one of those walls.

And I also agree - unless you are pumping water separately to each of those chambers (which you can certainly do), you won't get water past the first level.
 
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And I also agree - unless you are pumping water separately to each of those chambers (which you can certainly do), you won't get water past the first level.
Won't the water pumped into C overflow spilling into the two lower chambers, B and D, then from there into the still lower ones, finally spilling into the main pond itself?
 
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hmmm... Ok. Maybe. If the walls between the chambers are lower than the wall between C and the pond. However, are A, B, D and E also designed as bogs? Or is just C the bog?
 
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hmmm... Ok. Maybe. If the walls between the chambers are lower than the wall between C and the pond. However, are A, B, D and E also designed as bogs? Or is just C the bog?
If there is some way to plum the smaller chambers as bogs too, then fine, but I don't know if that is possible/realistic.
 
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Well if you did plumb them all as bogs, you'd need to have multiple lines - one feeding each bog. Like I said, do-able, but a lot of extra work. Two thoughts:

1. Why not make it one big bog? You can still have water exit into the pond from the two ends, or have it flow over the wall in various spots, whichever you prefer.
2. If you choose to use only the middle as a bog, the other separate chambers will, I imagine, need some kind of agitation to keep them from just collecting debris in the bottom. Maybe an air stone in each? A jet? I don't know - I just imagine those being four stagnant pools. Water will flow over the top, but it won't necessarily stir up the bottom.

What's the idea behind the separate chambers?
 

brokensword

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If there is some way to plum the smaller chambers as bogs too, then fine, but I don't know if that is possible/realistic.
IMO, it would be easier to just make C the bog and have the water overflow to each side, filling B and A to eventually spill into the pond. As said above; make A and B gravel filled to gain some sort of biofiltration. You'll have to keep your water contained so it can ONLY exit toward B on both sides. Same going from B to A.

To me, this seems easiest and gains you a bog + waterfall cascades.
 
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brokensword

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Ah... but sideways down the back of the pond? I'm a bit slow when it comes to drawings - just ask my husband! - so quite possibly I am missing the point!
no, down each side from C toward B then toward A; he'll have to contain the water within each chamber so it doesn't overflow, though it probably wouldn't hurt anything if going toward the pond.
 
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50’x50’, it probably weighs over 700lbs.
50 X50 I WOULD LEAN TOWARD CLOSER TO 1100 POUNDS . If memory serves me correctly my liner was 30 x40 and that was 700 pounds

YOUR DESIGN IS FESABLE YES a little more challenging yes. Seeing a picture of your style helps in working with a design . but if i was to design what you have done i would look at the stack slate walls by aquascape. they are semi circular and would look very cool in your design. but they are not cheap either.


With only a 20 inch lift and having three drops that's only 6 3/8" inches per drop not a lot but it doesn't have to be either. how ever with a bog in that space you'll need to have higher sides if you plan to put plants in the steps . this will probably remove line of sight on your 6" steps from anywhere but straight on and because your looking through the bog in the steps you won't see the steps or the water cascading at all. even the bottom drop of 6" with plants growing and dropping you may not see the 6" at all.

A 20 inch drop in a singular but double dropping fall can be very stimulating and i would bet with the soils your about to pull out you could get to 30" easily and that my friend is one amazing possibility

I can see you are working hard at a plan and taking advise from some posts here but have you been researching on you tube or surfing across this site? The other note i can see is each step will need to be recessed inside itself so that the water doesn't splash and leach out as it falls to the next step. so can it be done yes is it a challange and some potential issues need to be worked out yes.
df.jpg

Not nit picking we get so many who come here just trying to help as your ready to drop some good money on a good size pond.

1. Is the pond close to the house ?

2. With the three steps you probably won't see much of a cascade is these steps visible from the house or patio?

3. your design is leaning toward contemporary but it is large which is unusual for contemporary.? Is that the look your going for?

4. have you seen some of the builds on you tube team aquascape , tussey landscaping, the pond digger, Atlantis water garden ?

5 you have a natural slope does it come down toward the house? Theres so much you can do with that natural slope
 
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Ah... but sideways down the back of the pond? I'm a bit slow when it comes to drawings - just ask my husband! - so quite possibly I am missing the point!
I just tried to show that as a narrow bog and small drops and plants you won't see anything.
 
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1. Is the pond close to the house ?

2. With the three steps you probably won't see much of a cascade is these steps visible from the house or patio?

3. your design is leaning toward contemporary but it is large which is unusual for contemporary.? Is that the look your going for?

4. have you seen some of the builds on you tube team aquascape , tussey landscaping, the pond digger, Atlantis water garden ?

5 you have a natural slope does it come down toward the house? Theres so much you can do with that natural slope
1. The pond is about 12 feet from the house, though still quite visible. I wanted to have it right under one back window, but that limits traffic too much.

2. The pond is low enough, the entirety of the pond is visible from the back windows. The waterfalls will be visible, they just aren't very tall. The effect maybe more of a sluice than of waterfall, but I don't know how the bog slows or affects the flow from the 4k gph pump.

3. As for style, I was inspired by this perfectly circular swim pond. I arrived there after watching many Pond Guy videos, realizing that if I didn't have $10k+ of stone, I would end up with "uncanny valley"-like affect where I knew it wouldn't quite look right, and instead decided to go for a completely unnatural look, which of course means I only need $1.5k in bricks.

4. I have been watching tons of videos from YouTube from various professional pond builders, though none seems similar to the design I'm using.

5. There is a natural slope. I set the bricks of the pond on a level, so the pond ignores the slope and I was able to lay the bricks fairly level to water, not the slope. The slope is such that the top rim of bricks is flush with the ground at the back.
 

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