Taking water from bottom of the pond and sending it to a bog filter. Is this crazy?

[combatwombat]

To start, I am not doing this. I had a brief discussion on Youtube w/ an Australian guy named Kev about this. He runs a channel called Ozponds. Very knowledgeable guy. Has built lots of ponds and has some in-depth instructional videos about the finer points of bog building.

He's building his "dream pond" right now. One feature of this pond is that he is using jets to push water from one end of his deep end (about 6' deep) to the other, and is then placing a pump in a vault at that end to collect this muck water and send it to his Aquascape-esque wetland (snorkel/centipede style of build).

My initial reaction to this was, of course, that it will clog his wetland and cause him lots of problems. His response was that he expects to have to backflush the filter once per year or so, that a filter isn't worth having if there's no way to backflush it, and that he thinks the benefit of doing this will outweigh the work of backflushing the bog.

He's built dozens of bog filters and I've built... well... less than one at this point. So who am I to argue!?

Curious to get opinions about this from you folks. Is Kev headed for certain failure or is this an enlightened approach that is worth adding to the "how to build a pond" playbook?

 

[GBBUDD]

Not at all .. I have two main drains that both are at the 6 foot deep end ofvthe pond and they clearly are on the very bottom. They suck in the plant matter and it intern is pumped to the strainer basket within the external pump. This is the first heavy sediment trap. Water in my set up is then sent to the 24 in culvert and like I said before the water is discharged against the wall to stop circulation as quick as possible I'm looking for displacement not flow. 4 years latter and I still get next to nothing out of the culvert/ centipede and that pipe in pitched and has a 1 foot depression where tge snorkel Meets it. Hell I have fish liiving in this 24 inch pipe fry made it all the way through the listed above.
I feel on larger ponds that circulation jets are invaluable I pump 12000 but I only send about 6000 to the bogs and I send the rest to the return jets. These aided the skimmer when it was being used in a huge way. From what you have said there's nothing out of the ordinary .

Ed balue of Aquascape who designed this process talked to Atlantis gardens jack. About tge entire concept of tge bog if you haven't seen it find it. He describes the force of the water ejecting broken down denitrous and this can be found in older bogs that are left alone. It's not a problem seeing this . And again after 4 years my water level in the snorkel is barely if at all higher then is the water level at tge surface of the bog

 

[Rashad]

CW I’m at the same point as you but am going to install an oase eco premium pump. The pump will be in my intake bay, but I’ll have a satellite intake near the bottom of my pond to circulate some water from there as well. I don’t anticipate any problems? My plan is to have 75% flow from the intake bay and 25% from the bottom but that’s adjustable in case i need to change it. All that is getting pumped into the bog.

 

[combatwombat]

@GBBUDD: I've probably seen the video you mention because I'm addicted to all those Youtube pond channels, but it's been awhile. So you don't see an issue w/ pumping solids into the bottom of your wetland? The bacteria will gobble it up?

You said you have a strainer basket ahead of the pump. In this case, the "strainer" would just be the slots on the pump vault and the cage around the submersible pump's intake.

Also, I didn't realize you have return jets on your pond. Where did you place them and how did you plumb them. Flex PVC? What size outlet? Were you shooting for a specific GPH for each jet?

In this case, Kev's jets will be at the very bottom of his pond to push detritus to his pump, which will feed the wetland.

@Rashad: Ah, intersting setup. I like it. So you'll put a tee or wye or something on your intake and control flow from each location with a ball valve or something?

I like this idea. I was trying to figure out how I would implement this plan if I wanted to do something similar. I didn't want to place the pump deep in the pond because that would make it hard to service and also would eliminate skimming. And I didn't want to have two pumps pushing to the wetland. Splitting the input makes more sense.

Do you anticipate clogging issues on the intake @ the bottom of the pond?

I love the idea of using jets and an intake at the bottom of the pond to keep it clear of detritus, but it seems like flirting with danger.

 

[GBBUDD]

@GBBUDD: I've probably seen the video you mention because I'm addicted to all those Youtube pond channels, but it's been awhile. So you don't see an issue w/ pumping solids into the bottom of your wetland? The bacteria will gobble it up?

You said you have a strainer basket ahead of the pump. In this case, the "strainer" would just be the slots on the pump vault and the cage around the submersible pump's intake.

Also, I didn't realize you have return jets on your pond. Where did you place them and how did you plumb them. Flex PVC? What size outlet? Were you shooting for a specific GPH for each jet?

In this case, Kev's jets will be at the very bottom of his pond to push detritus to his pump, which will feed the wetland.

@Rashad: Ah, intersting setup. I like it. So you'll put a tee or wye or something on your intake and control flow from each location with a ball valve or something?

I like this idea. I was trying to figure out how I would implement this plan if I wanted to do something similar. I didn't want to place the pump deep in the pond because that would make it hard to service and also would eliminate skimming. And I didn't want to have two pumps pushing to the wetland. Splitting the input makes more sense.

Do you anticipate clogging issues on the intake @ the bottom of the pond?

I don't know if you read my build or not but you may want to .....Yes flex pvc and i got vortex jet heads from sacramento koi for the return jets........Yes i have about 3000 gph at both heads maybe a bit less. the heads are pushing in the same direction as was the waterfall, This also pushed everything right toward the skimmer....... yes the strainer basket in the pump does a great job grabbing plant and animals from getting to the impellere......... i disagree with using that energy at the bottom of the pond. wind and nature will blow god know what at the pond. i feel the faster you address these the better the jets circulate everything right toward the skimmer and or to the intake bay where you want flaoting drbris removed before it sinks to the bottom i have main drains if they get that far.

 

[combatwombat]

@GBBUDD; Thanks, sir. I've actually read every word of your entire build thread. But after 50 pages of discussion, the details start to get a little foggy.

 

[GBBUDD]

yeah i was thinking of doing a build only a lessons learned and what i could not find online and what i know now .

 

[combatwombat]

yeah i was thinking of doing a build only a lessons learned and what i could not find online and what i know now .

Would love to see that. I would like to do the same at some point. I have a text file with half a novel's worth of calcs and tips I've picked up to test on my build. Want to eventually circle back around and share what worked/what didn't.

 

[GBBUDD]

One of my videos is a floating go pro and i just droped it in the pond at the waterfall and let it video and record the trip around the pond it was in the skimmer in two trips around the pond . thats where i think that energy is best used. This also created a whirl pool from the main drain . even at 6 feet below it was pretty cool

 

[Rashad]

The pump I mentioned has a built in second inlet with variable flow control, off, 25%, 50% 75% or 100%. You could achieve the same thing with a diverter or tee and ball valve but this seemed simpler. Not too worried about clogging. It’s a solids handling pump up to 3/8 of an inch I think and that’s about how big my slits in my pvc will be, plus I’ll have a prefilter on the intake at the bottom. If it stops working I can just divert 100% flow to the intake bay until I can clean it out.

@GBBUDD: I've probably seen the video you mention because I'm addicted to all those Youtube pond channels, but it's been awhile. So you don't see an issue w/ pumping solids into the bottom of your wetland? The bacteria will gobble it up?

You said you have a strainer basket ahead of the pump. In this case, the "strainer" would just be the slots on the pump vault and the cage around the submersible pump's intake.

Also, I didn't realize you have return jets on your pond. Where did you place them and how did you plumb them. Flex PVC? What size outlet? Were you shooting for a specific GPH for each jet?

In this case, Kev's jets will be at the very bottom of his pond to push detritus to his pump, which will feed the wetland.

@Rashad: Ah, intersting setup. I like it. So you'll put a tee or wye or something on your intake and control flow from each location with a ball valve or something?

I like this idea. I was trying to figure out how I would implement this plan if I wanted to do something similar. I didn't want to place the pump deep in the pond because that would make it hard to service and also would eliminate skimming. And I didn't want to have two pumps pushing to the wetland. Splitting the input makes more sense.

Do you anticipate clogging issues on the intake @ the bottom of the pond?

I love the idea of using jets and an intake at the bottom of the pond to keep it clear of detritus, but it seems like flirting with danger.

 

[GBBUDD]

The pump I mentioned has a built in second inlet with variable flow control, off, 25%, 50% 75% or 100%. You could achieve the same thing with a diverter or tee and ball valve but this seemed simpler. Not too worried about clogging. It’s a solids handling pump up to 3/8 of an inch I think and that’s about how big my slits in my pvc will be, plus I’ll have a prefilter on the intake at the bottom. If it stops working I can just divert 100% flow to the intake bay until I can clean it out.

That sounds like a trash pump as they call it and i have never seen one that was designed for constant use but thats just my knowledge maybe there is

 

[Rashad]

That sounds like a trash pump as they call it and i have never seen one that was designed for constant use but thats just my knowledge maybe there is

I hope not! Here it is. https://www.thepondguy.com/product/oase-aquamax-eco-premium-pump/submersible-pond-pumps

 

[Lisak1]

Here's my take on the issue - we don't ever really get into it here, but there is definitely math involved in building a bog. When you hit the ideal water flow point into a bog, the water should stay in the bog long enough, and move slowly enough, that your heavy solids will sink to the bottom of the matrix. (This obviously would not apply to an all gravel bog.) Ed Beaulieu discusses this in some of their really super sized bog builds. But if you're moving the water too fast, you will just push the debris to the top where it will get caught into the gravel, in my opinion. (I don't pump debris to my bog, so this is all theory.)

We do have a clean out snorkel in our bog - the water to the bottom is crystal clear. The bog is slanted to the snorkel side, so if there was anything to settle, it would be there. Fine sediment moves very quickly through the bog, so I'm 100% sure we failed that math test! No mechanical filtration happening in my bog.

As a result we are in the process of setting up a temporary fines filter - just an inexpensive gravity fed filter box with Matala pads and a pump. We'll run it until the water is acceptably clear again. We are finishing year 9 and moving into year 10 with our pond, so that's not so bad. We just reached the point where the amount of fines floating around became unpleasant to the most important viewer (me!) and takes way too long to settle when things get stirred up. We do know the fines settle in the down flow bog - anytime the water level gets low, we can tell by the amount of cloudiness in the water.

 

[combatwombat]

Thanks for the detailed response, Lisa. I've had the same thoughts about the math of bog building. There are definitely numbers to hit to get optimal performance at the smallest size, but bogs seem to be very forgiving, so you can overbuild them and/or change a lot of other variables about how you send water to them, and they'll still perform great.

Are you thinking this fines filter will just be something you run every once in awhile when it seems like you need it? Have you also considered just reducing the flow to the bog to see if those fines will settle there?

 

[Lisak1]

Exactly. There's something called the... um... "linger" time. haha. Not the right word, but my brain is on zero percent right now. Anyway it's the time that the water spends moving up through the gravel, allowing the sediment to settle to the bottom. If one gets the math right then that's the result.

As for bacteria breaking this stuff down, I'd say yes it will... up to a point. But it won't ever just go away. If that were the case we would have a planet without soil! The organic material will only break down so far. Leaving, you guessed it - sediment! (My husband and I have this discussion all the time. He wants to add bacteria to the pond - he believes that will eat all the fine stuff. I win the argument 100% of the time. Doesn't stop him from bringing it up again! haha!)