New pond - bog filter, waterfall or both?


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My son and I are just about to start digging, and of course I start reading about bog/wetland filters. I've already got my kit with skimmer, 16" waterfall filter, 3000GPH variable pump, liner, etc. (here is the kit: https://www.amazon.com/gp/product/B06XSSPCFM/).

I was planning on a roughly 9x10' by 2' deep pond with a small waterfall. My landscape is flat, so don't want to install a volcano waterfall, but more of a stream with 6-12" drop into the pond for aeration. But now I'm thinking about turning that stream/falls into a bog filter, or perhaps some sort of combination. Just 12-15" deep pea gravel, enough for plants to root in.

A couple concerns:

1. Is the full volume of water from the pump going to be too much for a bog and/or plants? The pump has a variable control, so I'm able to dial it down. Alternatively, I could design the bog with more of a stream in the middle with planting areas to the side. Another option is to split the flow between bog and a separate waterfall.

2. Is 12-15" of gravel enough depth for plants?

3. I know top-down flow is not the best for filtration, but will it feed the plants with enough water and nutrients to thrive? My skimmer and waterfall already both have filter mats and bio balls.
 
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addy1

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I know top-down flow is not the best for filtration, but will it feed the plants with enough water and nutrients to thrive? My skimmer and waterfall already both have filter mats and bio balls.
The problem with top flow is the gunk gets layered up on top of the gravel. I had two top flow small bog filters on a pond of mine. It was a constant battle to keep the top layer of gravel clean so it would not run out of the whiskey barrel but would run into the pond.
 
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The problem with top flow is the gunk gets layered up on top of the gravel. I had two top flow small bog filters on a pond of mine. It was a constant battle to keep the top layer of gravel clean so it would not run out of the whiskey barrel but would run into the pond.

OK, good to know. So perhaps I should keep the waterfall and bog separate? I could put in a "T" and have half the flow going to the waterfall filter, and the other half going to the bog.
 

addy1

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Sure you can T it, I have a T part of the water goes to my 1000 gallon pond, most goes to the bog.
 
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You can have both, send the water into the bog and have it rise up through the gravel and flow back to the pond via a waterfall.
Most of us with bog filters send the water through distribution pipes that have slits cut in them. The pipes are covered with 12" of pea gravel. Plants are grown directly in the gravel, no pots. Some of us add a clean-out stack. The end of the distribution pipe is turned up vertically and ends right above the gravel surface. There you have a screw-on cap. If your water flow slows down, you can open the cap to flush it out.
 
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The more I think about a bog filter, the more I like it. The pond itself at 8x10' and 2' deep is only going to be about 550 gallons. I have a variable pump up to 3000GPH, so what size PVC pipes in the bottom of the bog would be appropriate?
 
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the concern i have is the loss of gph due to head pressure. 300 GPH SPLIT BETWEEN A BOG AND A WATER FALL 1500 each subtract head pressure from the bog and the length of the pipe and the flow is going down down down . i imagine you got a waterfall bio falls but i would lean toward just building a bog higher then the pond and let the bog have the flow and when it comes up to the tp of the bog you have a section thats lower then the rest of the sides and you get your water fall . heres what the different flows look like
 
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Yes, I'm a bit concerned about the flow as well. I didn't get a biofalls, but a smaller Savio 16" waterfall which came with my kit. It does have a filter mat and a bag of bio balls, but much smaller than the biofalls model.

For decent flow, it might be better to have a hybrid "bog" which would be more like a planting area in between two falls. The top falls would be the 16" filter falls, drop 12" into the "bog" which I'm thinking would be about 3x4'. Then another 12" drop into the pond. If I channel the majority of the water into a meandering stream, perhaps that will be enough to feed the plants.
 
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I did a bog and a waterfall. But I didn't have enough liner at the time for both, so I started with the waterfall, and then added the bog on the other side of the pond later when I had more liner. I really like it that way, actually. I like that both sides of my pond have interesting, eye-catching visual features. I like that I get a little extra surface agitation from where the water flows back into the pond from the bog. I also like knowing that, since my waterfall also has some gravel and plants in it, if my bog pump ever fails on me and I don't notice right away, I'll still have some filtration. And if the waterfall pump ever goes out, I'll still have some aeration from my bog.

It's been a lot of fun to have both! The downside, of course, is that I have to have extra pumps and they both have to be hidden in the pond and cleaned out regularly. But that's fine with me!
 
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If you suspend your pumps from a rope to keep them a bit off the bottom, they might not clog up so fast, if at all.
Nice idea! I'll have to see if I can make that work. I don't really have anywhere I could easily anchor any ropes from. Do you have any suggestions for that?
 
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@AlyssaFish What kind of pump do you have? Does it have treaded intake and output?
Yes, I believe they both do. I don't know much about pumps, but it sounds sorta like you're asking if they're both inline pumps? They are, but only the one for the bog is being used that way (it's intake hose is attached to a skimmer). Did that answer your question?
 
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@AlyssaFish I have one of these. Once you figure out how to keep it from popping apart it works great. It’s threaded so I have a 90 elbow threaded to the pump and threaded pipe into the elbow and the cage. Pump is zip tied to a brick. Anything that gets stuck on the cage eventually rots or softens up enough that it is sucked into the line and into the bog. Never needs to be cleaned.
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Nice idea! I'll have to see if I can make that work. I don't really have anywhere I could easily anchor any ropes from. Do you have any suggestions for that?
It's also a good idea to have a rope on your pump for pulling it out of the pond. You never want to pull it out by the electrical cord.

My pump has a handle. I have a thin rope tied to the handle and the other end is wrapped around a large rock on the shore. If you don't have a large rock, you can always use some kind of stake, like a tent stake, a stick, pole or pipe driven into the ground. If your pump doesn't have a handle, wrap the rope criss cross around the pump and (or) around it's output pipe.

I found that my pump doesn't clog anymore when kept off the bottom. The bulk of debris seems to settle on the bottom.
Every so often, maybe every couple of months, I'll use my net to slowly scoop the debris off bottom.
 
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Thanks for the advice, guys! I'm excited to look into these options!
 
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I have a bog and a small waterfall. I was in the same boat as you this time last year as I had planned for a waterfall and filter but not a bog. Then somebody on here who shall not be named :) got me interested in a bog. I had already bought my pump and feared the pressure would be too high but you control that with a good quality valve. My bog is about 6’ x 3.5’, filled with pea gravel to approx. 14” deep. The bog then flows over a drop of about a foot into a small basin and then into the main pond which is 20’x13’ and averages 4’ deep. Works fantastic and I would not change anything.
 

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