Filter Issues.

[Brian Montague]

When I built my bog this Spring, the water went from solid pea soup green to crystal clear within a week of starting up the bog.
Previous to the bog startup I could only see my fish when they came to the surface to eat.
After startup of the bog I could see clearly three feet down as I said, within a week! It is absolutely amazing. And that was even before any of the plants in the bog were established. It was just the gravel filtering and colonizing the beneficial bacteria.

My bog is a lot bigger than yours needs to be since my pond is a bit under 1800 gallons.
You can build a very simple bog with a window box planter or a small stock tank. A PVC pipe with slits cut into it laying in the bottom of your container covered with pea gravel. The water gets pumped from the pond through the under gravel PVC pipe, then rises up through the gravel and flows back to the pond. Plants are grown right in the gravel, no pots. Your container can sit right at the edge or partially over your pond so that the water pours back into the pond. If necessary, you can cut a small notch in the container top edge as a low point for the water to flow out of and into the pond.
If this sounds complicated, it's not. It's very simple and you won't regret it. You will have crystal clear water with zero maintenance. No rinsing of filter pads every other day. Just sit back and enjoy your pond.

Any questions?...just ask...

Dear Poconojoe, thanks to yourself and your fellow bog filter enthusiasts I'm enormously relieved that I can improve my fishes' life in a relatively simple way by using home made stuff. I'm going to Google my way round to getting appropriate planter boxes, plastic piping, pea gravel and marginal plants. Massive thanks all round, I am now one happy Brit! Brian M

 

[poconojoe]

When I built my bog, my pipe feeding the bog goes over the wall between the bog and pond. It is mostly hidden by stones. I didn't make any penetrations in the rubber liner.
If you find the need to penetrate the waterproof container that you are using, I highly recommend using a bulkhead fitting for a water tight seal. They are inexpensive and come in many sizes to fit with whatever size PVC pipe you choose to use. They are two parts that screw together with a gasket. Some have interior threads which you can screw your pipe into and some don't have threads which you can glue your PVC pipe to.

 

[Brian Montague]

Dear Poconojo, I was thinking of building the bog in a container made of fish friendly plastic which would take away the need for a liner. I had a look online at some animal feed troughs and just wrote to the manufacturer to make sure that the HDPE it's made from is the appropriate one. Regards, Brian M.

 

[poconojoe]

Dear Poconojo, I was thinking of building the bog in a container made of fish friendly plastic which would take away the need for a liner. I had a look online at some animal feed troughs and just wrote to the manufacturer to make sure that the HDPE it's made from is the appropriate one. Regards, Brian M.

Sounds good.
Thinking about what size your bog should be. Generally, if you have fish, they say your bog surface area should be at least 30% of your pond surface area.
12 inches of pea gravel is the recommended depth. Try to have extra height above your gravel in case the water level rises for some reason.

 

[brokensword]

Dear Poconojo, I was thinking of building the bog in a container made of fish friendly plastic which would take away the need for a liner. I had a look online at some animal feed troughs and just wrote to the manufacturer to make sure that the HDPE it's made from is the appropriate one. Regards, Brian M.

the tub should be fine; my liner is made from hdrpe.

 

[Brian Montague]

Hi Poconojo, thanks yet again for your advice, 12" of pea gravel and 30% of the surface area of the pond sounds fine. plus an extra couple of inches of trough above the top of the gravel Am I right in thinking that the pipes that carry water from the pond should be set up drilled or part sawed to let the water through and be fixed together on the bottom of the bog filter trough under the pea gravel? I was thinking of tilting the trough very slightly so that the water cleaned by the plants then rises up and returns to the pond via a pipe fitted to the top of the nearest edge of the trough and maybe I could fit a sponge filter in there to trap any debris to prevent it returning to the pond. I'll have a good look at everyone's links to their own set ups before I start making my own. Thanks again everyone, Brian M.

 

[brokensword]

Hi Poconojo, thanks yet again for your advice, 12" of pea gravel and 30% of the surface area of the pond sounds fine. plus an extra couple of inches of trough above the top of the gravel Am I right in thinking that the pipes that carry water from the pond should be set up drilled or part sawed to let the water through and be fixed together on the bottom of the bog filter trough under the pea gravel? I was thinking of tilting the trough very slightly so that the water cleaned by the plants then rises up and returns to the pond via a pipe fitted to the top of the nearest edge of the trough and maybe I could fit a sponge filter in there to trap any debris to prevent it returning to the pond. I'll have a good look at everyone's links to their own set ups before I start making my own. Thanks again everyone, Brian M.

you've got the basic idea. Monitor your output pipe return to the pond; make sure it's enough so there's no backup. And I'd not put anything between the bog and pond as if it fills up and you're not aware, the water could rise high enough and begin leaking out of your tub bog. The idea of a bog is that it is a bio filter, not a mechanical filter. You can pre-filter, though, but I'd not 'post' filter. And the idea of keeping some height re liner or tub is that as the gravel starts to fill with either debris or roots, that the water will not have as easy a path out and will rise higher than you first anticipate. By having this extra height, you're guarding against this.

 

[Brian Montague]

you've got the basic idea. Monitor your output pipe return to the pond; make sure it's enough so there's no backup. And I'd not put anything between the bog and pond as if it fills up and you're not aware, the water could rise high enough and begin leaking out of your tub bog. The idea of a bog is that it is a bio filter, not a mechanical filter. You can pre-filter, though, but I'd not 'post' filter. And the idea of keeping some height re liner or tub is that as the gravel starts to fill with either debris or roots, that the water will not have as easy a path out and will rise higher than you first anticipate. By having this extra height, you're guarding against this.

Got It!!!! Thanks yet again. Brian

 

[poconojoe]

You got the basics.
No filter after the bog. As mentioned, if you did add a filter and it clogged, your water would be backing up and overflowing out of the bog.

If you decide to drill any holes in the "tub", I would advise the use of a bulkhead fitting for a perfect seal. I think I mentioned that before.

There are a couple ways you can build your under gravel manifold pipe. You can drill holes or cut slits in your manifold pipe. If you cut slits, cut them 1/3 through the PVC pipe. I spaced mine 1-1/2 inches apart. I have two manifold pipes each is around 10 feet long. Since your setup is much smaller, you might want them spaced closer.

You can face the holes (or slits) up or down. It seems to be a matter of opinion on that choice. I faced mine up, figuring they might get blocked if any sediment collected on the bottom.

I have a clean-out stack at the end of each manifold pipe. (I have two manifold pipes). The end of the pipes have a 90 degree fitting facing up. The pipes end just above the surface of the gravel. I have a screw cap on each one.
If the water returning to the pond slows down, I'll turn off the pump, unscrew the cap, turn the pump back on and watch black water shoot out for a few seconds. (I shoot it into a nearby flower bed). This forces out anything that may have collected inside the manifold pipe. After that, the water runs full force.

I keep a rope tied to my pump for easy removal and to keep it off the bottom. This prevents the pump from picking up heavy debris that has settled on the bottom. I use a net to scoop that stuff out.

Oh, the water traveling through your bog should be relatively slow for best filtration.

 

[addy1]

All great advice above!

 

[Brian Montague]

You got the basics.
No filter after the bog. As mentioned, if you did add a filter and it clogged, your water would be backing up and overflowing out of the bog.

If you decide to drill any holes in the "tub", I would advise the use of a bulkhead fitting for a perfect seal. I think I mentioned that before.

There are a couple ways you can build your under gravel manifold pipe. You can drill holes or cut slits in your manifold pipe. If you cut slits, cut them 1/3 through the PVC pipe. I spaced mine 1-1/2 inches apart. I have two manifold pipes each is around 10 feet long. Since your setup is much smaller, you might want them spaced closer.

You can face the holes (or slits) up or down. It seems to be a matter of opinion on that choice. I faced mine up, figuring they might get blocked if any sediment collected on the bottom.

I have a clean-out stack at the end of each manifold pipe. (I have two manifold pipes). The end of the pipes have a 90 degree fitting facing up. The pipes end just above the surface of the gravel. I have a screw cap on each one.
If the water returning to the pond slows down, I'll turn off the pump, unscrew the cap, turn the pump back on and watch black water shoot out for a few seconds. (I shoot it into a nearby flower bed). This forces out anything that may have collected inside the manifold pipe. After that, the water runs full force.

I keep a rope tied to my pump for easy removal and to keep it off the bottom. This prevents the pump from picking up heavy debris that has settled on the bottom. I use a net to scoop that stuff out.

Oh, the water traveling through your bog should be relatively slow for best filtration.

Once again, many thanks for your help poconojoe and everyone else who has been so helpful to me. Brian M.

 

[GBBUDD]

play, tee boxes

Don't feel band I'm a yankee and I have no idea eather

 

[GBBUDD]

cut slits

As more and more manufactures are going to thin kerf sicular saw blades thats a pretty thin cut . I'd double cut or place the cuts closer together

 

[Brian Montague]

The plumbing can either enter at the bottom of the box (you'd probably need some sort of bulkhead fitting) or, an easier method, use a 90 degree elbow and drop it down the inside of the box to the bottom.

Dear Lisak 1, One thing I need some advice on - so, the water pumped from the pond enters the bog filter and is taken to the bottom through a pipe. I understand that bit but does the pipe carrying this water (and leaking it steadily through holes or slits into the gravel) have to be in a particular pattern, ie is it like a snake, albeit one with right angled joints or do a number of smaller pipes run off a central pipe and are capped at the ends. I hope I'm making myself clear. Regards, Brian M. ps I've just seen a video by the pond digger who shows how he builds the plumbing for his bog filter - he uses a big central pipe and slightly smaller pipes bracketed to that and slots and holes are drilled and cut in the pipes and brackets and caps as necessary. So I think I know the answer to my own question.

 

[GBBUDD]

There's no right or wrong answer just answers on which might work a little better then others. The slits are the option i like best but i prefer a solid 1/8" cut 6 inches apart . with the slits facing downward. i would go as far as slipping a little rubber under these slits so it a piece of gravel is vibrated by the current it's not working on the liner but on a piece of scrap. The other way i'd look at it is the force of the water will once the bog begins to get used the pressure will build and change in the pipe so i believe the slits don't need to vary too much i could be wrong im not an engineer but as the debris breaks down in the bog the pressures will change and work on the next least are or resistance.