HELP ME UNDERSTAND BOGS :)

Mmathis

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.... not how they perform as filters. I kinda got that. I'm having trouble conceptualizing the physical set-up, what goes where, what's in-line with what, etc. Several of you have posted diagrams for me in the past, but can't find them when I search :( All I'm really clear on is that you want the water to go to the bog BEFORE the bio-filter.

1. Does the bog sit higher and flow into the main body of water or other way around? Seems like I've seen it mentioned both ways, which is confusing me -- or it may be that I don't follow the terminology(?). If so, how do you know which way is best for your needs?

2. Can you run a bog and a bio-filter off the same pump? Why, why not, & how? And, yes, because of my box turtles being so messy, I'll want the extra filtration.

3. I always see mentioned a percentage of your total pond (some say total pond volume; some say total surface volume...) that can be "bog." Is that a minimum or a maximum number? If you go over that number, would it matter? The way I understand it is that percentage or ratio is for optimum "filter" performance.

Not SURE about a bog yet, but still THINKING about it :) May be too much for me to handle to start, but looks like might be something that can be added on in the future... If I do, plan to go the liner & pea gravel route.
 

addy1

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My bog sits higher than my pond, water falls back into the pond. You could run two filters off the same pump, as long as you have the water flow from the pump.
The larger the percentage the more filtering you have. My pond is around 9-10k without the stream and small ponds, the bog is around 2500k gallons
 

Mmathis

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The water that goes to the bog: does it go directly from the pump, to the bog, then flows back into the pond?
IOW, making it's own "circuit," or ..... ?

I was looking around on-line last night and saw a company that makes a diverter connection that allows you to run 2 "features" off the pump. So I would need to be sure I had a pump strong enough to handle both. How strong (or weak) does the flow need to be that goes to the bog? If too strong, is there a way to cut back on the "bog" flow?
 

addy1

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With ball valves and two lines you can control the flow pretty easily. I have full flow going into the bog.
Mine is set up to go directly into the bog then it waterfalls back into the pond. We have a separate pump for our stream, our pond pump cannot handle the head pressure to get up the 45 foot slope.
 

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addy did you already tell her about the tube thingy w/ the holes that you use to push the water down into your bog gravel? Can't remember if you did or not and too lazy to search back and see.
 
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All I'm really clear on is that you want the water to go to the bog BEFORE the bio-filter.
Oops. Not really true. First, the bog is a bio filter. There is a chance that a pond would have such a large ammonia load that some ammonia would make it through the bog and therefore to another bio filter, lets call it a Skippy just to conceptualize. So if there were a Skippy after the bog there would no ammonia for it to convert. Of course the same might be true the other way around, Skippy first then bog the bog might not get any ammonia. But then ammonia conversion is rarely 100% per pass, it takes several passes. But in any case the order of bio filters doesn't affect ammonia conversion.

This gets a bit confusing in Water Garden circles because generally all filters are called bio filter and rarely does the ponder know what it is they're trying to remove. A filter is just thought of as needed, or that it will "clean" water whatever that means.

Whoever told you the bog should be first might have been thinking the bog should be used as a settling chamber. It is true that if you pumped poop into the bog it would probably get trapped there, but it would still decay. So not really a very good settling chamber. Any decent bio filter would never clog so it shouldn't matter if poop goes through the bio filter first or not. In either case any design that allowed waste to accumulate in any bio filter, including a bog, is a poor design imo. However, bogs to collect more stuff and do clog, but generally are so large that the clogging takes a long time.

1. Does the bog sit higher and flow into the main body of water or other way around? Seems like I've seen it mentioned both ways, which is confusing me -- or it may be that I don't follow the terminology(?). If so, how do you know which way is best for your needs?
Bog works the same either way. Most common is bog higher.

2. Can you run a bog and a bio-filter off the same pump? Why, why not, & how? And, yes, because of my box turtles being so messy, I'll want the extra filtration.
Either way, there's no difference. Moving ammonia past bacteria is what converts it. One pump splitting to 100 filters or 100 pumps pumping to a single filter. However blowing water through a filter isn't an efficient use of electric so most people want a slow flow through filter. This concept has morphed into a myth that slower flow is a requirement for conversion but that's not true.

3. I always see mentioned a percentage of your total pond (some say total pond volume; some say total surface volume...) that can be "bog." Is that a minimum or a maximum number? If you go over that number, would it matter? The way I understand it is that percentage or ratio is for optimum "filter" performance.
For converting ammonia the size of the bog has no relationship with the size of the pond. The bog has to handle the fish load which really means the amount of food being fed. The entire concept of bio filters in Water Gardening comes from the Koi Pond hobby. Unfortunately the logic for bio filters didn't really come along with the filters and in Water Gardening bio filters are magical things that seem to fix everything if you have one of any size. Few people even measure ammonia levels.

The reason bio filters are so important in Koi Ponds is the amount of food they will feed fish in warm months. They'll feed 3% of body weight per day which can be 10 to 20 pounds of food per week. I doubt there is a single Water Gardener on the planet that has used 10 pounds of food in an entire year, and many won't use 10 pounds of food in years.

Most Water Gardens do not need any bio filter at all.

So there isn't really any way to determine the proper size of a bog because there is no data. Koi Pond owners measure and keep data but don't use bogs any more. 15-20 years ago they did, they were called gravel filters. But good data was hard to come by because gravel filters were too natural to provide good data. And Water Gardeners use bogs but don't measure or keep data. They just use a gut feel type estimate, but there's no data to show if this works. If you build a 100'x100' and it works it doesn't mean a 1'x1' bog wouldn't have worked just as well. Bigger is certainly more opt to do whatever it is you want done.

Other use for a bog
Bogs have another use in Water Gardens and that is in killing unicell algae. It's more hit and miss than ammonia conversion for complex reasons, but a bog filter has a good chance of killing unicell algae and creating clear water. Add to that a bog's ability to trap small bits and they can produce very clear water. Key word is "can", not will. The chance of clear water can be improved by increasing the length of a bog. This can be done in any foot print by winding a bog channel. A bog is just a subsurface stream. It can be very shallow, even 4", but I like 8" to 12".

Length, not size
If you have a 10'x10' bog and pump the water in one end and it flows out the other the size of the bog is 10', the direct line from pump to out flow. Doesn't matter how wide the bog is. The water doesn't travel in exactly a straight line but close enough. If the pump spreads the water over the width of the 10x10 the size of the bog is still 10' as each source of water travels about 10'. That's good for ammonia conversion, but not for killing algae.

For killing algae you want the algae to be in close contact with the killer bacteria. As the algae goes by one killer bacteria the algae takes a hit and weakens. Passing another weakens it more, etc. Given enough hits the algae wall pops and the lucky bacteria eats the creamy center. I think a long ride through the dark bog would weaken the algae too, less sun, less energy, less they're able to produce the chemical that attacks the algae killing bacteria, but I haven't seen any studies on that so just my own personal theory.

The algae and bacteria fight each other with chemicals. A bog can give the bacteria the upper hand. This is unlike ammonia conversion because ammonia doesn't fight back. Ammonia converting bacteria always wins, there are few variables. You can almost set your watch by the conversion rate.

High end Koi Ponds use UV filters instead of bogs because UV is 100% effective. They don't like hit or miss because they're right on the fence. In their case green water can actually kill fish. In Water Gardens green water generally helps fish.

Keep it simple
All this sound really confusing? Learning the basics can greatly reduce the confusion. Unfortunately the basics are almost completely missing from the Water Gardening hobby and that makes it more confusing unless you go with the flow and just set up a single Skippy which works because it isn't needed.

Basic #1, know what it is you're trying to filter. Ammonia? Solids? Suspended particles? Unicell algae? Tannins? Etc. That allows for a specific discussion and keeps a butt load of complexity that has nothing to do with the specific goal from entering the discussion. Forget about "combo" filters.

Basic #2, use standard terms. Bio filter is ammonia conversion. Settling chamber removes solids from the water column before decomposition. UV kills unicell algae. Etc. When a person says bio filter to remove poop the discussion gets really confusing.

Basic #3, measure. To remove something you first have to have that thing present. For example, most Water Gardens measure zero ammonia without any man made bio filter. Then they talk about needing to add a bio filter. That's confusing. How does one discuss the proper size or configuration of something that does nothing? Makes my head spin. Measurement is also used to determine if a filter is performing. This concept is also almost completely missing from Water Gardening. If the pond looks good the filter is deemed to be 100% effective. But without measuring results you're just spinning your wheels and that is confusing.

These concepts will allow you to focus in on smaller targets and reduce confusion.
 
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OK here's a question... I have a depth of pea gravel through my river area. I would like to bury a couple lines of pipe that have been drilled full of small holes and attached to a pump - the goal being to pump water up through the gravel. Does it really matter that the gravel is 6-12 inches below the surface of the water, as long as there are a lot of plant roots growing through it? I have some grasses growing in the gravel already, but want to get the pipes put in place early next season so the roots have a chance to really grow around the pipes.

I have a fairly high water turnover, so its no big deal to divert a little water underneath the gravel. And there's always the option of adding another pump specifically for this. I put the gravel down as a base for the plants to grow in, but I also want to make use of it for filtration... Every little bit helps because I'm betting I will have a much higher fish load in a few years as some of the babies survive.
 
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Does it really matter that the gravel is 6-12 inches below the surface of the water, as long as there are a lot of plant roots growing through it?
I assume you're talking about filtering ammonia?

What function do the plant roots perform? Taking up nitrogen? I would assume the roots would fill and clog the pipe holes pretty fast. What kind of grass is this?

Having the gravel submerged doesn't change the performance of ammonia conversion much. That's not to say this would be a good bio filter. If you were going to the trouble of burying pipes and such there are easier to build bio filters which convert ammonia in a more reliable way. Gravel filters, or maybe undergravel filter, is a more proper name for a bog when used as a bio filter. These were abandoned like 10 years ago for high fish load ponds. They were huge compared to newer bio filters and their ammonia conversion would fall off pretty fast due to channeling. They also aren't well thought of for aquariums either.

Every little bit helps because I'm betting I will have a much higher fish load in a few years as some of the babies survive.
Measuring and knowing is more reliable if you're talking about fish loads that actually require bio filters.
 

addy1

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OK here's a question... I have a depth of pea gravel through my river area. I would like to bury a couple lines of pipe that have been drilled full of small holes and attached to a pump - the goal being to pump water up through the gravel. Does it really matter that the gravel is 6-12 inches below the surface of the water, as long as there are a lot of plant roots growing through it? I have some grasses growing in the gravel already, but want to get the pipes put in place early next season so the roots have a chance to really grow around the pipes.

I have a fairly high water turnover, so its no big deal to divert a little water underneath the gravel. And there's always the option of adding another pump specifically for this. I put the gravel down as a base for the plants to grow in, but I also want to make use of it for filtration... Every little bit helps because I'm betting I will have a much higher fish load in a few years as some of the babies survive.

I have my pea gravel up high enough so only a little water sits on the gravel before it flows into the pond. I have plants that like dry crowns, so they are on mounds of gravel to keep the crowns dry, but the roots wet. I prefer it this way, grab all the filtering via roots, plants, gravel before it heads back into the pond.

The gravel in your stream will help with the filtering if you set it up the way you mention. I have some pea gravel in my stream and in the stream ponds they are planted with plants and pea gravel, more filtering. In the spring they do need to be cleaned due to the fact the dirt settles in the small ponds.

For the past 20 plus years my ponds have been filtered with bogs, up flow gravel filters, gravel filters whatever you want to call them. The water tests on all the ponds have been perfect, the water has always been algae free, never have green water. Crystal clear water. A small amount of string algae near the lily pots, no massive amounts have ever grown, except in my arizona pond and only in june, then it poofed away lol.

My bog has two pipe lines running the length of the bog, water flows up through every inch of the gravel, 27 feet long 5 feet wide. When we set up the pipes we made sure there where slits cut into the piping every six inches to a foot apart. No sign of channeling. It is easy to test, I just dig a depression in the gravel, then you can see the water filling that depression, bubbling up from below.

I went through 10 lbs of food this summer, waterbug, so yep us water gardeners do use food lol We have over 150 fish, and i am sure more will be around next year with spawning season.

I did test the water every week for a month, then every other week, then once a month as the readings never showed anything except perfect water. The only issue I have fought was low ph, we have acidic well water and low ph rain, even that has balanced out.

Long and short of it, I love my bog and will stick with my bog, my pond loves my bog and so do the fish.
 
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Waterbug - This is not meant to be my primary filtration... I currently have two 55-gal skippy-type filters in use. However the gravel is in place and I thought perhaps it could be useful in providing extra filtration, plus since its a different type of media from my main filters, it may help clean the water in different ways. My understanding for bog filters was that they should be heavily planted because the plants themselves provide substantial cleansing of the water - thus my comments about the plant roots.

The water continuously flows over the surface of the gravel now, as it is located in a stream, but it seems that other than the surface area, the rest of the gravel is just sitting stagnant. That's why I thought adding some pipes with holes into the gravel bed would help push water through more surface area of the available gravel. At the very least, perhaps it will reduce that amount of waste that settles into the gravel. I originally thought that the waste settling in the gravel would just provide food for bacteria, but I think there has to be some flow of water too, or the waste just collects and dirties up the pond.
 
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First off, I'm a huge fan of bogs for Water Gardens. It is my #1 pick for Water Gardens, followed by streams.

I do not consider them any good whatsoever for Koi Ponds or any serious fish load pond.

I often read people saying "not all the ponds are the same"...I agree...they aren't. But then almost in every discussion every pond is considered the same. "If thing X worked in my pond it'll work in every other pond". Any filter, not matter what it is, should be considered in the context of a specific pond and the specific goals of the owner. Abby, it's great you've been happy with bogs. I've always been happy with every bog I've ever had. For my next pond I'm thinking of having a very heavy fish load. A bog would be a very poor choice for that pond. I'll probably still install a bog because I like them for other reasons. But I will not consider it to be adding any bio filtering because they are no reliable for high fish loads. It will of course add some bio filtering, but not to the degree that this application will require.

Filters are impersonal objects to me. I have no interest in them beyond a tool to get a specific job done. If someone were to do experiments and provide good data that contradicted all the current data and showed bogs were better bio filters than say a Trickle Tower, Shower, moving bed, etc., I'm more than happy to change my mind. Delighted.

Shdwdrgn, you're probably correct, but I have no idea what it is you're trying to filter out. I have no idea what species of bacteria you want to grow and what kinds you don't want to grow. I have no idea what you think is a "much higher fish load". You asked:
Does it really matter that the gravel is 6-12 inches below the surface of the water
The short answer is it doesn't matter. Because I know nothing about your pond or your goals the additional info I gave was of a general nature thinking you might have been interested in further research. However, I'm very confident that whatever setup you create you will be very happy with it as most Water Gardeners are.
 

Mmathis

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Those of you with bog filters: can you post either a diagram of how your entire pond (everything) is set up, AND/OR a simple description of how it's (whole pond including bog & any other "features") set up. Just anything that would help me get a mental picture of how they look.

Also, would be interested in hearing what your bogs look like & how & why you chose that style. What shape (long vs. wide), depth; how much gravel & is it flat or graded; what is your water-flow set-up like; what plants work best, etc, etc, etc?

Remember, newbie here, so be kind :)
 

addy1

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lol newbie, click on the link in my signature, I have posted my set up in my build thread if you wish to see it.

The size shape was dependent on the slope of our land, which is really sloped. The bog was made on the downhill side of the pond to help have a good 5 foot high wall of dirt to make the bog and pond level.
 

Mmathis

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ADDY -- Oh I did look at your build! That may be the spark that started my interest. The thumbnails show up, but the other images (early in the post) showed up but not as links I could follow.
 
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I am with Mmathis this bog thing is very confusing :) Addy maybe next year you can post a video?? Please please I want to add a bog to my current pond next Spring and I am more of a watch and learn kinda girl..please please.
 

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