Bog filter questions

[ChrisK]

A 3600 gph pump when it is pushing it's max head the flow rate drops drastically.

To go along with the 18 feet in vertical height you will also have to add how far the bog is lineal distance from your dyi skimmer and also the amount of elbows ect, in order to accurately determine your head pressure.

Just a gut feeling i would lean toward trying to get the bog down a bit in height. While there are pumps that can handle 18 feet without issue . the problem is the cost of the pump and the amount of energy needed. But what your looking for is a high head pump.

First, my apologies to all of you. My 18 foot number is the length from pond to bog.
The head height to the bog is 8 feet. Sorry for the confusion on my part. Most of the grade is within the top 8 feet (so more downward pressure at the upper end) of the 18 foot length. There will only be one bend in the 2" flexible PVC where it connects to the skimmer, all other bends will be inside the bog itself. I have an old Danner Model 24 pump I was looking to use-if possible. It's rated at 2400 gph with a max head of 17 feet (1400 gph @ 9' head). Thats what I was going to start with as a test. Any suggestions are very much appreciated.

Thanks again, and sorry for the wild goose chase.

 

[GBBUDD]

Hard to comment not seeing the pond it's size and bio load demand

 

[ChrisK]

Hi again,
I have another question for all of your boggers.
I have a small elevated area in my bog that I can't remove (plastic drainpipe & tree root).
It will add about 4" to 6" to the grade of the bog bottom, but nowhere near the wall height of 18".
Should I run the manifold over this area for circulation, or just line it and fill with gravel?
Water height will be 12", so water would be "sitting' in this area.
Your advice is appreciated. Thanks.

 

[combatwombat]

Hi again,
I have another question for all of your boggers.
I have a small elevated area in my bog that I can't remove (plastic drainpipe & tree root).
It will add about 4" to 6" to the grade of the bog bottom, but nowhere near the wall height of 18".
Should I run the manifold over this area for circulation, or just line it and fill with gravel?
Water height will be 12", so water would be "sitting' in this area.
Your advice is appreciated. Thanks.

Are you saying you have a protrusion in one area of the bottom of your bog? Where is it in relation to the rest of the footprint of the bog?

 

[GBBUDD]

The shape of a bog can be literally be anything . the main idea is to have a minimum of 12 inches of gravel above a manifold of pvc or even flex pvc. placed at the bottom of the bog and spaced a foot apart or less. IF there's a rock a pipe what ever it may be keeping you from a uniform bottom just have a pipe on each side of the supply pipes.

 

[ChrisK]

Okay, Thanks.
I'm thinking I'll just slope the manifold over the pipe in that section of the bog.
It's only a small area that cuts across one corner of the bog. About 1/10th of the total bog floor.
I didn't think it would be an issue but wanted some input from someone with more experience.

 

[Koi4JT]

Hello All,

I've built a couple of ponds in the past, but all were mechanically filtered.
At our new house I'm building one and have just discovered Bog filtering.
This site looks like an Excellent place to get some good advice. Thanks in advance.
Pond will be about 1600 gals. Bog will be about 470 gals.
I will have fish in the pond (maybe Koi, but they outgrew my previous ponds, and are kinda destructive/messy). We'll see.
Bog will be at the top of a steep grade, and I would like to have a waterfall as well.
I've been researching this, and I have some questions. I'll list them below.
What is the best height difference between the bog walls and outflow for the bog?
Should I combine the bog output and the waterfall? (I'm trying to use one pump in a DIY skimmer), or would I be better off with 2 seperate pumps?
I've read about the flow rates for the bog which seem slow for a waterfall. I can send pictures if they will be helpful.
I'm sure I'll have more to ask after I get some of your wisdom on these first few.

Thanks again.

Your 470 gal. bog is plenty big. So long as the top water surface is above the top water surface of your pond, you should have no problem. Essentially, the bog is a small pond filled with pea gravel. Water is fed into the bog via a "H" shaped PVC manifold with 1/4" holes drilled into the "H" sections every 2-3 inches. I put a check valve on the supply piping to the bog to prevent the dirtiest bottom water from syphoning back into your pond if the pump stops, think power outage or the pump dies. From the top, I installed a "U" shaped channel the feed the surface water of the bog down into a short plastic waterfall. The top of my bog is about 18" above the top of the pond. I also plant pond grasses in the bog to help eat the nitrogen produced by the fish. I also have Irises and some other plants in an attached side pond, for the same reason. The pond water is virtually clear all year long and the only chemicals I use are to neutralize the chlorine in makeup water. You should note that the top of the bog is where most of the pond crap accumulates, such as algae and sludge. I clean this periodically by removing some of the bog's side block wall, plugging up the discharge channel and letting the sludge overflow away from the bog. During this time, I also use a hose to somewhat pressure wash the surface pea gravel. The algae I just pull out by hand as it is usually thick and easy to remove. Also, I use only one mag-drive pump. By the way, I have a whole bunch of Koi and goldfish. This was a very fertile year for the fishes...

 

[GBBUDD]

with 1/4" holes drilled into the "H" sections every 2-3 inches.

Slots cut 1/3 the width of the pipe that are 1/8" wide is what i'd recomend over the drilled holes they can never fully clog by rocks or sludge

 

[Koi4JT]

Slots cut 1/3 the width of the pipe that are 1/8" wide is what i'd recomend over the drilled holes they can never fully clog by rocks or sludge

Neither ChrisK nor my ponds are anywhere near the size of yours, both being below 2,000 gallons. In regard to a slotted manifold, constructing one would be quite difficult. Drilling 1/4" holes completely through the 3/4" piping has provided ample flow of water through the almost 3 feet of pea gravel (in my design) and will work just fine. The water is pumping out from the pipe and pea grave is typically larger than 1/4". I also covered my "H" manifold with 1" thick coarse filter media. With bog plants, the bog need to be fairly deep to prevent roots from getting intro the piping. The filter media helps to prevent this. JT

 

[Lisak1]

Neither ChrisK nor my ponds are anywhere near the size of yours,

I don't think the size of a pond matters in this conversation. I would go with slits over holes for the same reason mentioned, but many have used holes drilled in PVC with great results.

covered my "H" manifold with 1" thick coarse filter media.

Were you at all concerned that would clog from the bottom side with debris, algae, etc?

 

[ChrisK]

Here we go with yet another question. I'm progressing SLOWLY on completing the bog and manifold. Rain has been an issue-but at least it's not snow.The bog has approx 8' head height above the pond.
This question is pump related. Does anyone have any experience regarding the Alpine Cyclone pumps?
I am looking at the Alpine Cyclone 4000. I'm also looking at the Pondmaster Hy-Drive 5100.
I have previous experience with the Danner/Pondmaster brand and found them reliable. Pondmaster is more $ than the Alpine.
Don't know anything about Alpine. Either pump will be used in my (Ozponds) DIY 5 gal. bucket skimmer, so size is a consideration.
Any other pump suggestions are appreciated. Thanks.

 

[GBBUDD]

Not familiar with either of those, sorry

 

[Oh pond]

Hey, I'm in progress of building a bog too. Pond's about 13x18x3 deep, bog under construction around 5x12x1 foot deep. Couple of things I thought I'd throw out there....
If you have a protrusion in the base of your bog if it extends out and affects plumbing,

be mindful of gravity and how that will impact water flow and how crud will collect in low spots of the bog.

Also, if $$ is much of a consideration, solid sch 40 PVC is much cheaper and glues right on your flex PVC. also, I believe you add 1 foot of head for each 10 ft length of pipe, and add 1 ft of head for each 45° bend (or 2qty 30° bends) even if they're positioned in your bog, it's still resistance your pump has to overcome to pump.

 

[Oh pond]

Hey, I'm in progress of building a bog too. Pond's about 13x18x3 deep, bog under construction around 5x12x1 foot deep. Couple of things I thought I'd throw out there.... If you have a protrusion in the base of your bog if it extends out and affects plumbing, be mindful of gravity and how that will impact water flow and how crud will collect in low spots of the bog. Also, if $$ is much of a consideration, solid sch 40 PVC is much cheaper and glues right on your flex PVC. also, I believe you add 1 foot of head for each 10 ft length of pipe, and add 1 ft of head for each 45° bend (or 2qty 30° bends) even if they're positioned in your bog, it's still resistance your pump has to overcome to pump.

 

[poconojoe]

Hey, I'm in progress of building a bog too. Pond's about 13x18x3 deep, bog under construction around 5x12x1 foot deep. Couple of things I thought I'd throw out there....
If you have a protrusion in the base of your bog if it extends out and affects plumbing,

be mindful of gravity and how that will impact water flow and how crud will collect in low spots of the bog.

Also, if $$ is much of a consideration, solid sch 40 PVC is much cheaper and glues right on your flex PVC. also, I believe you add 1 foot of head for each 10 ft length of pipe, and add 1 ft of head for each 45° bend (or 2qty 30° bends) even if they're positioned in your bog, it's still resistance your pump has to overcome to pump.

I'll add that you can use wide (schedule 40 pvc) sweeps instead of using standard 90's and 45's. They will allow for a little bit of less resistance for your pump.

On another note...
I think someone might have mentioned using a check valve so if the power goes out the water in your bog won't drain back into your pond. Emptying the bog is not a good idea. Your plants might dry out and die.
However, it's been said that a check valve may easily clog under the conditions of our ponds due to algae and other natural materials.

Some people just drill a 1/4" hole in the bog pipe before it penetrates the gravel. Water will shoot out of the hole during normal operation so aim it towards the bog. If you lose power, the hole will act as a vacuum break.
I added a personal touch and feed a spitter statue off that hole with some clear vinyl tubing. So my spitter acts as the vacuum break. Normally water shoots out of the spitter statue and into the pond. If I lose power, air gets pulled into the spitter which breaks the vacuum and prevents the bog from emptying.