Question about bottom drain to gravity fed settlement filter vs. a pump with pond pump with strainer

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Hi. I hope to begin digging my first pond soon. For now I am googling, reading, and learning everything I can about everything there is. There is one topic I am struggling with and would like to get opinions - is it better to run a BD into a gravity fed settlement filter (GFSF) or to a pump which has a built-in strainer? It seems that, from what I read, majority approach is to use a GFSF. Recently I visited a local Koi/pond business and the gentleman there was telling me that running the BD directly into a pump which contained a built-in settlement basket was better because the force pull of the pump on the DB line would be stronger than that of the water trying to self-level and, thus, even better suction pull on the bottom-of-the-pond muck. Both approaches seem valid to me. Given my limited space, opting for the pump/strainer method is better b/c I won't have to allocate space for the GFSF. He showed me that cleaning the strainer in a pump unit was simple to do and, to me, seemed no more work than similar cleaning of a GFSF.

Here is what I have been able to determine so far (and correct me if I am wrong):
- pump with strainer will cost more
- not having a GFSF will save space
- to purchase a GFSF can be costly...
- ...but a GFSF can be made MUCH cheaper

Other than cost and space what other pro/cons exist between the 2?

(I do plan on also having a skimmer)

Thanks,
Randy
 

whiskey

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Hi Randy
i would personally gravity feed to sieve and pump to filters.
If you pump to chamber, your mincing all the muck, in your pond, into your pump and your soon require a new pump or cleaning out often.

if you go to sieve muck gone before filters, so less strain on filters. ive made mine as photo
hope this helps
whiskey
 

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I would also pick gravity, and a sieve, I mean if I got to pick anything. They do take a bit of understanding, careful planning and attention to detail on the build to get right. Connecting a pump to the drain is more of a brute force, hard to get it wrong deal.

It would depend a bit on what you're trying to remove. If it were just leaves and you didn't mind cleaning the basket often the pump is OK. I find pressurized strainers a real pain to take apart, clean, prime if needed.

For high end type setups I think people are mostly concerned about removing fish poo. That's really soft and would get pulled right through the strainer basket. And it decomposes fast so a sieve is preferred.

I think the idea that a pump would pull more stuff into the drain is incorrect, at least not much more. If you ever see a bottom drain in a pond with some muck and no tangential pond returns you will see a ring clear of muck around the drain but only an inch or two wide. It's the tangential pond returns (TPR) which move the debris, not suction on the drain. I know this is counter intuitive, but it's worth some research to verify before building. I wish the name was "bottom drain tangential pond return system" instead of just bottom drain. TPR are every bit as important as the hole in the bottom.
 
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I appreciate the input. Everything you all mentioned is something I wondered about. I believe I will can the idea of running the DB directly to the pump.

Again, due to limited space, I believe I will use a canister filter as opposed to a trickle bio filter. I see a lot of sites which tell me to "run a pump to a bio filter" and "to put a pump in the skimmer" but I kinda get lost after that - a pump in the skimmer *AND* a pump for the BD??? Does that mean I need 1 pumps and they both feed into the pond? I don't get it. Where would I find a basic guide on how to design a system? A 'getting started' list of guidelines for design and connections and how everything would/should go together for various configurations. For example:
- What height to place the BD output line where it feeds the sieve container? (water seeks its own level...place the 2" below what normal water level would be? At the lowest point possible? etc...)
- At what level to place the output from the sieve to supply the pump (1" off bottom to prevent fine sediment from getting run through the pump)?
- I assume my skimmer would bypass the sieve and be plumbed together with the line running from the sieve to the pump. Is this necessary or can I just have my skimmer dump directly into the sieve container (thus, saving on some plumbing complexity)?

Thanks,
Randy
 

whiskey

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Hi Randy,
I use to run pumped to filters but saw the potential in gravity feed systems and the advantage of sequance pumps [less power usage] but it took me ages, i mean ages , to get to grips with gravity.
With pumped its simple, put in a pump, pump hose to filter, return via gravity.
With gravity its a question of water line [height ] in pond......sieve unit goes in at same height and then pump comes in to play by pumping to filter or split to filters.
TRY TO IMAGINE POND WATER LEVEL,BOTTOM DRAIN,SIEVE, AND FILTERS WITH NOTHING RUNNING......EVERYTHING STAYS AT WATER LEVEL EXCEPT FILTERS THERE ON THEIR ON LEVEL. THE MOMENT YOU SWITCH ON, WATER WILL BE SUCKED/ PUMPED BACK INTO POND THUS BOTTOM DRAIN FEEDS SIEVE BY GRAVITY THEN PUMP FEEDS FILTERS AND RETURNS VIA GRAVITY ......EXCEPT IF YOU WISH WATER TO GO HIGHER THEN YOU WILL NEED TWO PUMPS OF THE SAME VALUE OR ONE PUMP IF ONLY PUMPING FROM ONE OF TWO FILTERS.
THIS PHOTO MAY HELP..NOT SURE OF YOUR LEVEL OF EXPERIANCE, DONT MEAN TO LOWER YOU ,JUST TRYING TO HELP, THAT ONE THING ON THIS FORUM WE ALL TRY TO HELP EACH OTHER.
WHISKEY
 

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Again, due to limited space, I believe I will use a canister filter as opposed to a trickle bio filter. I see a lot of sites which tell me to "run a pump to a bio filter" and "to put a pump in the skimmer" but I kinda get lost after that - a pump in the skimmer *AND* a pump for the BD???
One pump for skimmer and another for the BD is the simplest way. Sounds like you're looking for simple so I'll leave it there.

"Canister filter" is a generic term. Some can be gravity fed, others require a lot of pressure to push water through the media. So you'd have to settle on whether this will be a pressurized filter or not before designing the pond.

Where would I find a basic guide on how to design a system? A 'getting started' list of guidelines for design and connections and how everything would/should go together for various configurations.
Unfortunately there isn't really a single guide. Lot's of guides for simple water gardens, no filter, no skimmer, no BD. Just a pump and maybe a waterfall. Adding components creates many little choices, like pressurized filter or non pressurized, that change everything. So you either have to learn at least the basics of how each work to design a total system, or hire someone to do that work, or hope you get lucky.

- What height to place the BD output line where it feeds the sieve container? (water seeks its own level...place the 2" below what normal water level would be? At the lowest point possible? etc...)
At the waterline, not really below. The BD basically overflows into the sieve. So I put the bottom of the BD pipe outflow right at, maybe 1/2" lower than the desired waterline. Given a 4" pipe and not knowing exactly how the outflow is configured, it's a bit hard to say exactly when we're talking about inches. You can leave the out flow pipe long and cut it back after the pond is filled. Then you'll know the exact water level. For first time builders I'd say leave room to work around the out flow pipe to make your life easier and you can fix any "learning opportunities".

- At what level to place the output from the sieve to supply the pump (1" off bottom to prevent fine sediment from getting run through the pump)?
Depends on the pump. Basic categories are external, external with strainer basket and submerged. But for any of these I would not worry about running fine sediment through them, they can take it.

- I assume my skimmer would bypass the sieve and be plumbed together with the line running from the sieve to the pump. Is this necessary or can I just have my skimmer dump directly into the sieve container (thus, saving on some plumbing complexity)?
The simple answer is you can do either. I don't really want to go into how because that might be more complexity than you want. If you pick one it would be easier to explain.

I don't mean to be coy but there are people who post questions here that get really mad if the answer is more than a sentence and others who want to get to a desired goal and don't mind the time needed to understand what they're up against. In general people either become interested in all the details or scale back or hire it out. The details aren't fun for everyone. I don't know where you're at.

This is probably more than you want....

It does take some noodling...which I like. As Whiskey points out, water level is key. Single ponds need floating weir gates and such which are tricky. There is an alternative that makes gravity systems easier. Adding a second pond eliminates the level problem. The second pond, even if small and hidden, acts a reservoir. Pump pushes water into the main pond which overflows into a skimmer / sieve (no flap needed) or through a bottom drain into a sieve and other filters and then back into the smaller pond.

In the case of a bottom drain you might need a pump behind the skimmer which pumps back into the same main pond, not the smaller one. It is possible to get the bottom drain output and skimmer at the right level so both will work with a single pump, but you have to be dead on. In that case just make sure it's easy to adjust the drain out flow pipe up or down.

I think the most problematic part of a sieve is the floating weir which the second pond eliminates.

When the pump is turned on the small pond is drawn down until water charges the system and gets back to the small pond. Also, all evaporation shows up in the small pond, which can be startling, like 1' or more a day depending on pond sizes and weather. So an auto fill, if any, is placed in the small pond.
 
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Hi Randy,
I use to run pumped to filters but saw the potential in gravity feed systems and the advantage of sequance pumps [less power usage] but it took me ages, i mean ages , to get to grips with gravity.
With pumped its simple, put in a pump, pump hose to filter, return via gravity.
With gravity its a question of water line [height ] in pond......sieve unit goes in at same height and then pump comes in to play by pumping to filter or split to filters.
TRY TO IMAGINE POND WATER LEVEL,BOTTOM DRAIN,SIEVE, AND FILTERS WITH NOTHING RUNNING......EVERYTHING STAYS AT WATER LEVEL EXCEPT FILTERS THERE ON THEIR ON LEVEL. THE MOMENT YOU SWITCH ON, WATER WILL BE SUCKED/ PUMPED BACK INTO POND THUS BOTTOM DRAIN FEEDS SIEVE BY GRAVITY THEN PUMP FEEDS FILTERS AND RETURNS VIA GRAVITY ......EXCEPT IF YOU WISH WATER TO GO HIGHER THEN YOU WILL NEED TWO PUMPS OF THE SAME VALUE OR ONE PUMP IF ONLY PUMPING FROM ONE OF TWO FILTERS.
THIS PHOTO MAY HELP..NOT SURE OF YOUR LEVEL OF EXPERIANCE, DONT MEAN TO LOWER YOU ,JUST TRYING TO HELP, THAT ONE THING ON THIS FORUM WE ALL TRY TO HELP EACH OTHER.
WHISKEY

Whiskey - I get the basics of how the gravity system works and, to some degree, each possible component of a system. What I have struggled with is EXACTLY what your attached image shows - how to take it from concept to the real thing. Is it possible to get a better copy of that picture? Trying to read the words is a little difficult due to blurriness of the image.

"DONT MEAN TO LOWER YOU" - Not taken that way at all. I really didn't provide much insight as to what I do know and you took a stab at helping me (and you did)...much appreciated.

Thanks,
Randy
 
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"Canister filter" is a generic term. Some can be gravity fed, others require a lot of pressure to push water through the media. So you'd have to settle on whether this will be a pressurized filter or not before designing the pond.
Hum...ok. So the trade-off with pressurized and gravity fed then is size and costs, right? A gravity fed one, for about 1500 gal pond, would be pretty large but the cost to run a pressurized one could be quite high (because of the need for a stronger pump). Comparatively speaking, correct? Due to the location of my future pond, I really don't have the option of having a large gravity fed filter box and yet maintain aesthetics. But, I also can't afford an expensive smaller arrangement. I know my words of 'large' and 'expensive' are all subjective and leave little with you to help with - sorry about that. I will post more specifics on my situation later which will include pictures and reasons for my statements.

Unfortunately there isn't really a single guide. Lot's of guides for simple water gardens, no filter, no skimmer, no BD. Just a pump and maybe a waterfall.
Yea..I've found a million of those guides.

At the waterline, not really below. The BD basically overflows into the sieve. So I put the bottom of the BD pipe outflow right at, maybe 1/2" lower than the desired waterline. Given a 4" pipe and not knowing exactly how the outflow is configured, it's a bit hard to say exactly when we're talking about inches.
Maybe I am trying to make things more complicated than they are -or- I am looking for the 'right' way when there are, in fact, many right ways. Here is an example...you mention to put the BD outflow pipe at about 1/2" below desired water line but, up above, in Whisky's drawing he shows the line entering the filter box at about mid-level. Now, I may be reading too much into his drawing and it is just showing that the connection is made and not to imply at a certain level. If it just does not matter if the DB drain enters the filter box at the top, bottom, or middle, then that would be a perfectly acceptable answer also. I just don't want to build something once and then find out I made mistakes on the basic details.

I don't mean to be coy but there are people who post questions here that get really mad if the answer is more than a sentence and others who want to get to a desired goal and don't mind the time needed to understand what they're up against. In general people either become interested in all the details or scale back or hire it out. The details aren't fun for everyone. I don't know where you're at.


psst...I'll give you a little insight into my mind...I am a computer programmer by trade and an engineer by nature so I have a propensity to need to know and understand the details. that's why a high/mid/low level question is important to me. I don't mean to be a bug about those details - that's just the way I figure things out... So, I'm a details main. I want to know the details and, if it is going to get done, it will be by me and not hired out as I am a big DIYer when it makes sense.


This is probably more than you want....

It does take some noodling...which I like. As Whiskey points out, water level is key. Single ponds need floating weir gates and such which are tricky. There is an alternative that makes gravity systems easier. Adding a second pond eliminates the level problem. The second pond, even if small and hidden, acts a reservoir. Pump pushes water into the main pond which overflows into a skimmer / sieve (no flap needed) or through a bottom drain into a sieve and other filters and then back into the smaller pond.

In the case of a bottom drain you might need a pump behind the skimmer which pumps back into the same main pond, not the smaller one. It is possible to get the bottom drain output and skimmer at the right level so both will work with a single pump, but you have to be dead on. In that case just make sure it's easy to adjust the drain out flow pipe up or down.

I think the most problematic part of a sieve is the floating weir which the second pond eliminates.

When the pump is turned on the small pond is drawn down until water charges the system and gets back to the small pond. Also, all evaporation shows up in the small pond, which can be startling, like 1' or more a day depending on pond sizes and weather. So an auto fill, if any, is placed in the small pond.

"floating weir gates"? Guess I need to go read about that... :)
By using a smaller pond, what you are saying is that then the main pond will always be at 1 level...that makes sense. Although quite possibly not an option for me I am intrigued by the idea and need to go learn about that.

Listen, I appreciate all of the help - and yes, it was help. As I mentioned above, soon I will post details of my project and a proposed filter system design and get you guys/gals to chew it up.

thanks,
Randy
 

whiskey

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Randy

It does not matter in what position water enters filters/seives etc [ its the height of filter /seive box/unit,] forget for awhile where water enters, in gravity feed has to be at same height as pond, like waterbug said ,position of inlet 1" below water level is fine so long as filter box top is above pond level or it will over flow.
 
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So the trade-off with pressurized and gravity fed then is size and costs, right? A gravity fed one, for about 1500 gal pond, would be pretty large but the cost to run a pressurized one could be quite high (because of the need for a stronger pump).
Can be true, doesn't have to be. A fluidized bed isn't pressurized and is a state of the art bio filter and smaller than any other filter for the same bio load. Years ago pressurized filters were more common as bio filters. Now days I think they're only used for mechanical filters as a final polish (sand filter) or as a pre filter (bead filter)

To me pressurized means like more than double the pressure in an open pipe and also that the pressure would increase as the filter clogs. All these have some pressure of course.

Maybe I am trying to make things more complicated than they are -or- I am looking for the 'right' way when there are, in fact, many right ways.
Every pond is a custom job. Plus it's a bit surprising how fast the state of the art has changed. When I started the state of the art was an up flow gravel filter. Then submerged media, then bead, then trickle tower, then shower, then fluidized bed, and a few dead ends in between. Water garden techniques on the other hand stand still, completely unchanged in 15 years except maybe for better scams like barley straw to barley pellets to barley concentrate.

Here is an example...you mention to put the BD outflow pipe at about 1/2" below desired water line but, up above, in Whisky's drawing he shows the line entering the filter box at about mid-level. Now, I may be reading too much into his drawing and it is just showing that the connection is made and not to imply at a certain level. If it just does not matter if the DB drain enters the filter box at the top, bottom, or middle, then that would be a perfectly acceptable answer also.
Correct. I personally don't like to run the pipe thru the filter wall when DIY. It's more work, can leak and it can be a tight area to work in. I like the pipe to just dump into a sieve/filter/box. In my case the top of the filter is below the water line and would flow by gravity into a body, like the small pond, at the same or lower elevation. So the box doesn't overflow.

psst...I'll give you a little insight into my mind...I am a computer programmer by trade and an engineer by nature so I have a propensity to need to know and understand the details. that's why a high/mid/low level question is important to me. I don't mean to be a bug about those details - that's just the way I figure things out... So, I'm a details main. I want to know the details and, if it is going to get done, it will be by me and not hired out as I am a big DIYer when it makes sense.
Same here on all counts. I'm suppose to be coding instead of being here.

By using a smaller pond, what you are saying is that then the main pond will always be at 1 level...that makes sense. Although quite possibly not an option for me I am intrigued by the idea and need to go learn about that.
Yes, main pond is a constant full level. The look is great too as you never see water line marks on the sides, always looks full. I'd never do a pond another way.

Use the filter as the "small pond"...
So lets talk details...keeping in mind what Whiskey said a few posts back...when you turn on a pump it starts drawing down the water level in whatever box it's in. It takes some duration for the pumped water to fill pipes, streams, pond, whatever, and overflow back into the pump box. Say it takes 60 seconds and the pump is drawing 1000 gph, the pump box will draw down by about 17 gal. So the pump box would only need to be say 30 gal and it could act as the "small pond".

That all assumes the main pond, streams, etc are already at their full level. If the pump as been off for a day the main pond could be down by 100 gals by evaporation in which case the pump box would run dry. So it takes a bit of understanding. But then you know to top off the main pond before starting the pump.

Even if the pump box isn't big enough a garden hose can be run into the pump box to add water as the pump reduces volume. Gives you a bit more time. The down side is if the pump is turned off the pump box would overflow. But generally the pump runs 24/7 so not an issue.

The other issue is evaporation...it all accumulates in the reservoir (small pond or pump box). A small pond could go maybe a week before running dry while a 30 gal pump box might be dry in a day or two. That's fixed by putting a float valve connected the home water supply inside the reservoir. I supply the float valve to an automatic sprinkler valve on a timer as a backup since float valve to fail.

So the size of the "small pond" reservoir can be very small. All depends on the main pond surface area, stream, etc.

Drip water changes...
One more thing I'd throw in...something I've never done before but will on my next pond...drip water changes. Normally water changes are where you drain out some amount of the pond, 10% or 20% and fill with new water. There are a lot of issues with it, temp, pH, chlorine. The drip change is done with a drip emitter that is left on 24/7. So a 1 gph emitter would be an 11% change per week in a 1500 gal pond. At 1 gph you don't have to worry about chlorine, pH or temp issues and you never miss a water change.

I'd put a regular hose bib thru the pump box below the water line. I could run a hose from the bib to the garden to water plants. I could measure the amount of water coming out of the filter with a bucket and stop watch. Once dialed in I can forget it. And the auto flow would keep things topped off.

I bring this up because it ties into the pump box water line deal. I'd have to make sure the hose bib was above whatever in the garden I watered. With a raised pond it would be no big deal. An in ground pond, in a flat yard means I'd have to be really careful. Then again, I guess I could just put the bib in a pool in the waterfall. Either way, had to be thought though.
 
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It does not matter in what position water enters filters/seives etc [ its the height of filter /seive box/unit,] forget for awhile where water enters, in gravity feed has to be at same height as pond, like waterbug said ,position of inlet 1" below water level is fine so long as filter box top is above pond level or it will over flow.

"does not matter in what position the water enters the filters" - good and ok. an example of my concern is if water entered the top then leaves and such could settle better at the bottom vs water entering at the bottom and keeping *anything* from settling because the bottom keeps getting stirred up (to me, a difference on settlement thanks which had a bottom clean-drain...hard to flush it out if it is still swirling around).
 
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RANDY

These sites will help you divulge information at your own pace
whiskey

www.koiclay.com

www.koiphen.com

Thanks. I have spent quite a bit of time on koiphen also and enjoy reading that forum. I'll go scan the other one.

I hope I didn't offend by not providing details of my project. That was intentional with my original question to get general opinions about the two different systems (like the forced canister system causing a large power requirement - I didn't think it would have that much of an impact and is certainly something to consider as I do my research). I am aware that the details of my potential design do affect the final answer at a more granular level. Its just that the forced canister system seemed so much better in terms of space and cleaning effort that I wondered why I didn't see more about the use of them and wondered what I was missing.
 
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I redid my top pond last year. Added a bottom drain and skimmer box. The bottom drain goes to a 125-150 gallon tub which is my settling chamber. some simply use one, two or three 55gal rigid cans to make their settling chambers/vortex filters. From what I read it's more effecient to go this route so most of the stuff settles in there & does not get chopped up by your pump. You can run the pump directly off the bottom drain however you will need to empty the basket a lot more often. I just go out every week or so & open up my drain to let all the big stuff out.

I use 1 pump to run my pond which gets water from both my skimmer and bottom drain. I put a T valve so I can adjust the amount of flow I get be it more or less from the BD or SB.

Disagree with more sucking power with the BD hooked directly to the pump. If pump would be located in the same position no matter where it's sucking from there should be no difference in flow, it's just your pump will get clogged up more & your filter will have to work more due to getting blasted with more chopped up stuff.....

I think Sacrimento Koi has some nice pics/diagrams on how to setup a pond & might have better pics on what to do & not to do. They sell the larger canister filters among other things......

Filtration wise I went with a Advantage filter.... plug n play 6000 (purchased from someone on this site) & it's been doing a great job cleaning up the pond. The Performance Pro pump pulls around 450w of power but the ease of maintenance & also the ability to take pretty much any bio load is why I went this direction.
 

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