How Deep can a Deep Bog be Deep.

[poconojoe]

What I was thinking of doing was that skimmer bog combination, so lose some height of the hole by having the pond water overflow into the bog and pump the water back up into the pond from the furthest point in the bog to the opposite side of the pond.

This is the opposite flow as most or maybe all of our bogs.

The way you describe it, all the waste will just get deposited on the surface of the gravel. Not only might that be messy, maybe smelly or look bad, but it may hinder the natural breakdown that occurs under the gravel.
I'm no biologist, but it seems to me that under the gravel would be a better environment for the waste to break down. Above the gravel would be exposed to wind and sun, and the beneficial bacteria probably would just dry up and die.
There are probably better technical terms to describe this, so maybe the experts will chime in.

I pump mine from the opposite side of the pond, through a submerged black 1-1/2" flex PVC, up over the wall between the pond and bog. Rocks hide most of the flex PVC as it comes out of the water. The water gets pumped through the Flex PVC, then through 2" ridgid PVC, then through the 2" manifolds under the gravel. Then the water rises up through the gravel and returns to the pond in a natural flow.

 

[poconojoe]

Haha, ok, ok, bare with me

So "Bog Area" = for example 1 Foot deep area filled with gravel and drainage pipes, top of gravel would be mainly above water level. I would put plants in here.

Deep area = So that area is where the deep hole is, this area would be a part of the Bog area (one pond liner, no divider), just be a lot deeper, also be filled with gravel but would gradually slope to having gravel below water level in an area for different plants, and include a large barrel with holes in that would house the pump ("reservoir" in the video).

Waters Journey:
So pump gets turned on, water in the "reservoir" gets pumped into the pond, pond starts to overflow into the bog, water gets Aerated as it falls into the bog and takes all the debris from service of pond into the bog ("Skimmer").

The pond water with all its nutrients now flows through the gravel / plant roots. and eventually makes it's way into the deep area and into the reservoir to get pumped around again.

No? anyone? just me? o.o *

I think you are making it more complicated than it needs to be. Ultimately it's up to you, but your build seems like more work and in my opinion your water flow is backward. It's your pond/bog. Do what you want.

I suggest you look through addy's bog showcase, if you have not already. It's a long read with many discussions and thoughts from a lot of people.
I'll add a link to that and a link to my bog build....

https://www.gardenpondforum.com/threads/my-add-on-bog-build.26848/

Bog building, also called upflow filter, eco filter, wetland filter

I was asked to start a thread on how to build a bog. This is my rendition on bog building 101............. Building a bog: Before you decide to build a bog, you need to know what you want its primary purpose to be. Total pond filtration bog filtration combined with another filter. If you...

www.gardenpondforum.com

 

[TimL94]

That was why I made sure to link that video, so the concept of having debris being dropped into a lower area is already a thing people do with this Zero Edge design, I agree that a lot of leaves / mess could do with being removed as with any skimmer, just without a basket. But if that design that they are talking about in the video "works" surely the only thing that is missing is a bit more gravel area with plants in?

 

[mrsclem]

Agree with Pocanojoe, you don't want all the floating debris that a skimmer normally handles to end up on top of your bog! Most bogs are upflow.

 

[combatwombat]

@TimL94, sounds like what you're describing is a combo negative edge / downflow bog. It'll probably work, but most bogs are upflow because collective experience has found that downflow leads to quicker failure / increased maintenance with no way to back flush. That said, most people here with many years old upflow bogs seem to omit a backflush system as well and have had no problems. But at the end of the day, if your bog only 12" deep, it's not a ton of work regardless which direction your water flows.

I think there are some theoretical arguments that suggest upflow works better than downflow.

Edit to add: Just after typing this reply, saw this thread. Haha.

 

[GBBUDD]

So pump gets turned on, water in the "reservoir" gets pumped into the pond, pond starts to overflow into the bog, water gets Aerated as it falls into the bog and takes all the debris from service of pond into the bog ("Skimmer").

The issue with this is that water running over the top of the bog is not how a bog filter in the practice is. i know the video your referring to well. The intake bay it's advantage is when the water shuts down the water level is stable and theres little to no effect besides the debris tht was pulled in can float up and out.
The negative edge has is strong point as well as once anything goes over the edge it is gone it can not make its way back into the pond. i prefer the negative edge fall into a water area so that the debris can be collected easily. compared to falling directly into a disappearing stream where your debris gets pulled down into the rocks.

A bog FILTER is in how most here create it is to pump the water down to the bottom of a pit /bog and let the water rise slowly through the rock removing the micro items in the water. Thus creating clear waters.

 

[brokensword]

an integral part of all this 'upflow wetland filter' aka 'bog filter' is that you're running water past a LOT of surface area via the pea stone. This is where the nitrifying bacteria colonizes and is the real secret to upflow wetland filters. The plants are there to take up the resulting nitrate, which isn't nearly as lethal to fish.

The pea stone CAN also act like a mechanical filter but it's best not to make the bog filter do this because that's when clogging can occur. Having a settling area below the pea gravel and a slower flow through the stone, helps keep clogging from happening.

Running water over the surface isn't really going to gain you that much and as others have said, now you've let your surface debris collect in a way that is much harder to clean. I'd not think of my bog as a mech filter this way but more as a biofilter.

 

[Lisak1]

I agree with what's already been said - we have a negative edge with what is essentially a "down flow bog". Gravel on top, larger rocks, then aquablox, snorkel and centipede. This has been the highest maintenance area of our pond as we have worked to figure out how to make this function better.

We originally topped it with pea gravel - that had to go almost immediately as it clogs within days. As your pond ages it will clog within hours. So we were constantly raking the gravel to break up the "seal" that would form on the top as it would collect minute particles of organic material. We tweaked it and tweaked it until it's current state which is golf ball sized river rock on top of small boulders on top of the aquablox. Since this acts as our skimmer, we still have to clean out the leaves and other large debris, but it doesn't trap the minute stuff and drains very nicely. But if this were your bog, you would have constant issues with clogging, and it would be even harder to keep clear as you would have plants and roots slowing water down even more. Not ideal.

Now in nature, this is exactly how a wetland bog works with water flowing over the top - but those are generally acres and acres of surface area and the water can work through slowly.

 

[addy1]

Doesn't really matter. Make it how you want. Better to have any bog than no bog at all.

Yep some are shallow, some deep, some fancy, some basic.

Mine is around 2-3 feet deep, basic, just pipes, pea gravel, water and plants. No snorkel, no clean out pipes. It has been running fine for 10 years. My only maintenance is removing excess plant growth.

Water is always perfect, clear, never green, minor algae growth. No massive string algae. I would never have a man made filter taking care of my ponds.