Alternative to Settlement Tank

[max384]

I already asked this question in my pond build thread, but I'm not sure many people are following that, so I'll ask it again here.

I'm building a 2000 gallon pond with 4" bottom drain. It will have some shubunkins and koi, but I'm not planning on having it heavily stocked or a heavy fast-growth feeding cycle. I will be using a 4200 gph pump. I had originally planned on putting the pump right on the end of the bottom drain and pumping into the biolfilter until I was told this was not a good idea and that I should use a settlement tank. However, after reading up more on this, I found the settlement tank size should be 10% of the filter flow, which would mean I'd need a 400 gallon settlement tank, which I won't be able to do. So I could set up a mechanical filter before the pump, but I worry about how often this will need to be cleaned out. I was told it would need to be done up to daily, which is too much for me.

Here is a diagram of my previous pond plans before hearing about the settlement tank:

So what kind of options do I have here? Or have I already figured out the two possibilities?

 

[crsublette]

However, after reading up more on this, I found the settlement tank size should be 10% of the filter flow, which would mean I'd need a 400 gallon settlement tank, which I won't be able to do. So I could set up a mechanical filter before the pump, but I worry about how often this will need to be cleaned out. I was told it would need to be done up to daily, which is too much for me.

Yeah, as said in the Pirates of the Caribbean movie, the entire "flush daily and settlement tank size needs to be 10% of flow rate" code is more like a "guideline", that is if pirates were pond hobbyists.

Depending on the style of particulate mechanical filter, it can go before or after the pump and, depending on style, might only need to be flushed once a month or one a week or once a day.... First very important question...

How much space are you willing to reserve for the particulate filter? (not including space needed for plumbing and to "workaround" the filter)

 

[pecan]

Have you looked at getting a sieve instead? I went through the same thoughts and decided a sieve would be a much better option. You can get gravity feed that sit below the water level or pressurized that can sit above the water level. The pump goes after the sieve to whatever other filtration you have.

 

[Waterbug]

Yep, you're starting to see the issues.

Settlement tanks are a really old pond technology, probably the oldest. The hobby moved on from these long ago because better options were developed and because settlement tanks were almost worthless.

The trick is to understand why these types of filter systems were developed. They were developed to remove fish poo...nothing else. Yeah, they're remove leaves, dead algae, etc., but the reason for these systems is fish poo. Just like in the garden there's a big difference between fresh cow manure and a leaf mulch. Leaf mulch will take several years to break down. Manure is called "hot" because decomposition can be so fast and intense it gets hot and releases so many nutrients so fast that it can burn and kill plants. Fish poo is even hotter. It breaks down really fast.

So people keeping a lot of monster Koi have a serious poo issue. Ever see a dairy barn? So those people developed these BD systems to get poo out of the pond as fast as possible. Cleaning out poo once a week doesn't really do a lot of good because so much of it will have already broken down. Which is why sieves are almost a requirement for BD systems today.

Moving poo into a settlement chamber, vortex, bead, Skippy, or whatever doesn't really do very much because the poo is still in the pond. So those filters have really fallen out of favor.

I see a lot of people thinking a BD will keep a pond clean. When the Koi people say a BD keeps a pond clean they're referring mainly to poo. They still do other things to keep the pond clean. The higher up the Koi ladder you go you'll see less use of plants and the ponds will be covered (in a building). They get to a point where they only have Koi, water and poo. So in those systems a good BD system keeps the water clean.

That doesn't translate as well to Water Gardens. We do all kinds of things, like adding shelves and plants, that reduce how well a BD system works. Where as higher end Koi owners are designing ponds specifically so a BD system will work best.

This is a preference thing but I've seen ponds that I didn't considered "clean" but the owner was very happy about how clean the BD kept the pond. In most of those cases I was there because the owner had hired me to clean the pond. So "clean" is very subjective in Water Gardens.

There a lots of threads in pond forums about people with Water Gardens (called a Koi Pond) having to deal with string algae and clogged drains.

My impression is you just want a way to deal with the long term build up of organic matter. But it sounds like you also want some complexity too...this is kind of an unmentionable thing about ponds but many people seem to like more complex and costly solutions even though they say they don't. A few people do embrace their love of valves and filters.

I've already mentioned a vacuum system. Super simple and very effective but not too sexy.

A sexier choice is to make your pond into the settlement chamber. As you've already read people say 10%, or whatever, of the pond is the min size, but bigger is better. Well making the pond the chamber is 100% so that's pretty good. It's all the same water whether pond or separate chamber so why not?

Grrrr, software not letting me post a pic showing what this looks like...I'll try later if I remember.

The thing about the chamber being 10% is related to pump size. The thinking is that if you have a 5000 gal pond that you'd have a 5000 GPH pump and that kind of flow would need at least a 500 gal tank to have any hope of crap falling out of the water column and settling. People then developed Vortex shaped chambers to reduce the size, using current shapes to get crap to settle. Then bead filters to trap the crap, no settling, so smaller foot print.

So in theory you could just reduce your pump size. Where a 5000 GPH pump needs a 500 gal chamber a 1000 GPH would only need a 100 gal chamber. However, the problem then becomes pipe size. The flow inside a pipe needs to be strong enough to stop crap from settling inside the pipe. So 1000 GPH might mean you have to have a 1" pipe on the drain (I just guessed at the pipe size). Problem is a 1" pipe is going to clog a lot...especially in a Water Garden.

So that's how it goes. If a 3" is considered a minimum drain size that drives the requirement for a 1500-2500 GPH pump and that drives the settlement chamber size. Back to 10% of pond size....a single drain (3 or 4") will cover a limited area, 10-14'. So a bigger pond means multiple BD means more pump and we're back to more flow going into a single settlement chamber which has to be bigger...so we're back to saying 10% of the pond size as a ballpark estimate.

That's why making the pond the settlement chamber (if you really want a settlement chamber) works well. The only way to get lower flow, and therefore more settling, would be to build a settlement chamber that is larger than the pond. That's getting a bit too silly for most people.

The next sexy thing people like to do...especially for Water Gardens...is to build a custom super duper filter. I did this for a couple of years, it was great fun. Youtube has lots of custom invented filters to get you started. Virtually everyone makes some tweaks so it's their invention. Great fun.

So there are options. It really just comes down to exactly what your goals are and more importantly what kind of path you would like to take to get there. The path is the fun part. If we were talking about fish farming and trying to maximize $$$ almost all of this complexity, all these choices, would go away.

 

[max384]

Yeah, as said in the Pirates of the Caribbean movie, the entire "flush daily and settlement tank size needs to be 10% of flow rate" code is more like a "guideline", that is if pirates were pond hobbyists.

Depending on the style of particulate mechanical filter, it can go before or after the pump and, depending on style, might only need to be flushed once a month or one a week or once a day.... First very important question...

How much space are you willing to reserve for the particulate filter? (not including space needed for plumbing and to "workaround" the filter)

Whatever it is, I'd like it to be hidden. In other words, I'd like to bury it so that I could cover it with something to keep it as natural looking as possible. This being said, I would be able to make room for a tupperware type container, large outside garbage can, or maybe even a 55 gal drum. This is kind of what I had in mind:

With the filter media sheets easily accessible and removable for easy cleaning.

Have you looked at getting a sieve instead? I went through the same thoughts and decided a sieve would be a much better option. You can get gravity feed that sit below the water level or pressurized that can sit above the water level. The pump goes after the sieve to whatever other filtration you have.

That looks like an interesting option. I'm going to have to read up on this a bit more. I'd have to DIY one if I did, since I'm already way overbudget on this pond.

 

[max384]

Waterbug, you wrote your reply after I already started typing out a response. Yours is a long answer with a lot of info, and I'm only passing by the computer, so I'll reply a bit later once I get a chance to read through it!

Thanks for the help so far guys!!

 

[crsublette]

The cheapest I suppose is that you could also just fill up a container full of sponges and foam pads and this would work for ya as a particulate filter, but you would have to clean more often, that is whenever you can get to it.

The thread... Mechanical filtration choices disucssion (https://www.gardenpondforum.com/threads/mechanical-filtration-choices-discussion.12085/) ... talks about all sorts of options.

Since you are looking into burying it, then you could look into a gravity flow sieve since these sieves must be roughly below the pond's water level. My personal preference are sieves, but a sieve filter is the second most expensive particulate filter (around $700~1,500) unless you DIY it. There are all sorts of retail gravity flow sieves. DIY Concrete Sieve thread (http://www.koiphen.com/forums/showthread.php?135723-Concrete-Sieve) is about the cheapest DIY sieve I have seen, which is a gravity flow fed sieve that can be placed before the pump. However, this is a no pressure filter, which means the pump is restricted according to how much water flows into the gravity flow sieve.

To better understand how a sieve functions, then check out the thread, A brief explanation of Wedge Wire Sieve Filters (http://www.koiphen.com/forums/showt...breif-explanation-of-Wedge-Wire-Sieve-Filters)

There is also a vacuum pressurized Zakki Sieve (http://www.koiphen.com/forums/showthread.php?136154-Zakki-Filtration-System-Video&highlight=) that can be placed before the pump, which means you do not have the flow restrictions of a gravity flow sieve and the bottom drain pipe is much less likely to get clogged. This is what I use along with a very small bottom drain with just a 1" pipe. The sucker sucks in leaves and all sorts of big junk.

For fines filtration + bio-filter hybrid, look into possibly making your bio-filter a trickle K1 bio-filter + moving bed hybrid.... the below video talks about this the best. The sticky bio-film on the media actually works incredibly well for fines filtration, and, to clean it, you simply do a bypass so to stop pump flow, fill the bucket, turn on air stone to highly boil the media, do this for a hour or so, drain the bucket, now good to go, drain the bucket, resume operations as a trickle filter.

Instead of a centrifugal filter (http://www.waterco.com.au/component...ucts/filters/multicyclone-centrifugal-filters) for fine particulate filtration, then you can use the trickle+move hybrid filter or quilt batting or a sand & gravel filter or an aquaponic deep water culture (DWC) grow bed. A DWC is like one huge settlement chamber where you only grow plants and the high sedimentation period is what acts like a fines filtration, even though there is a small amount of aeration in it. I have not found a good DWC video just yet, also called a raft grow bed, but there are plenty of videos about them on the YouTube. The DWC would be placed after your primary large particulate filter.


So.... It all depends on how much space you want to sacrifice and how much money you want to spend and how much you want to DIY.

You have MANY choices... which many of the choices will be removed due to: 1) costing too much ; 2) you do not want to sacrifice the space foot print.

 

[max384]

Yep, you're starting to see the issues.

Settlement tanks are a really old pond technology, probably the oldest. The hobby moved on from these long ago because better options were developed and because settlement tanks were almost worthless.

The trick is to understand why these types of filter systems were developed. They were developed to remove fish poo...nothing else. Yeah, they're remove leaves, dead algae, etc., but the reason for these systems is fish poo. Just like in the garden there's a big difference between fresh cow manure and a leaf mulch. Leaf mulch will take several years to break down. Manure is called "hot" because decomposition can be so fast and intense it gets hot and releases so many nutrients so fast that it can burn and kill plants. Fish poo is even hotter. It breaks down really fast.

So people keeping a lot of monster Koi have a serious poo issue. Ever see a dairy barn? So those people developed these BD systems to get poo out of the pond as fast as possible. Cleaning out poo once a week doesn't really do a lot of good because so much of it will have already broken down. Which is why sieves are almost a requirement for BD systems today.

Moving poo into a settlement chamber, vortex, bead, Skippy, or whatever doesn't really do very much because the poo is still in the pond. So those filters have really fallen out of favor.

I see a lot of people thinking a BD will keep a pond clean. When the Koi people say a BD keeps a pond clean they're referring mainly to poo. They still do other things to keep the pond clean. The higher up the Koi ladder you go you'll see less use of plants and the ponds will be covered (in a building). They get to a point where they only have Koi, water and poo. So in those systems a good BD system keeps the water clean.

That doesn't translate as well to Water Gardens. We do all kinds of things, like adding shelves and plants, that reduce how well a BD system works. Where as higher end Koi owners are designing ponds specifically so a BD system will work best.

This is a preference thing but I've seen ponds that I didn't considered "clean" but the owner was very happy about how clean the BD kept the pond. In most of those cases I was there because the owner had hired me to clean the pond. So "clean" is very subjective in Water Gardens.

There a lots of threads in pond forums about people with Water Gardens (called a Koi Pond) having to deal with string algae and clogged drains.

My impression is you just want a way to deal with the long term build up of organic matter. But it sounds like you also want some complexity too...this is kind of an unmentionable thing about ponds but many people seem to like more complex and costly solutions even though they say they don't. A few people do embrace their love of valves and filters.

I've already mentioned a vacuum system. Super simple and very effective but not too sexy.

A sexier choice is to make your pond into the settlement chamber. As you've already read people say 10%, or whatever, of the pond is the min size, but bigger is better. Well making the pond the chamber is 100% so that's pretty good. It's all the same water whether pond or separate chamber so why not?

Grrrr, software not letting me post a pic showing what this looks like...I'll try later if I remember.

The thing about the chamber being 10% is related to pump size. The thinking is that if you have a 5000 gal pond that you'd have a 5000 GPH pump and that kind of flow would need at least a 500 gal tank to have any hope of crap falling out of the water column and settling. People then developed Vortex shaped chambers to reduce the size, using current shapes to get crap to settle. Then bead filters to trap the crap, no settling, so smaller foot print.

So in theory you could just reduce your pump size. Where a 5000 GPH pump needs a 500 gal chamber a 1000 GPH would only need a 100 gal chamber. However, the problem then becomes pipe size. The flow inside a pipe needs to be strong enough to stop crap from settling inside the pipe. So 1000 GPH might mean you have to have a 1" pipe on the drain (I just guessed at the pipe size). Problem is a 1" pipe is going to clog a lot...especially in a Water Garden.

So that's how it goes. If a 3" is considered a minimum drain size that drives the requirement for a 1500-2500 GPH pump and that drives the settlement chamber size. Back to 10% of pond size....a single drain (3 or 4") will cover a limited area, 10-14'. So a bigger pond means multiple BD means more pump and we're back to more flow going into a single settlement chamber which has to be bigger...so we're back to saying 10% of the pond size as a ballpark estimate.

That's why making the pond the settlement chamber (if you really want a settlement chamber) works well. The only way to get lower flow, and therefore more settling, would be to build a settlement chamber that is larger than the pond. That's getting a bit too silly for most people.

The next sexy thing people like to do...especially for Water Gardens...is to build a custom super duper filter. I did this for a couple of years, it was great fun. Youtube has lots of custom invented filters to get you started. Virtually everyone makes some tweaks so it's their invention. Great fun.

So there are options. It really just comes down to exactly what your goals are and more importantly what kind of path you would like to take to get there. The path is the fun part. If we were talking about fish farming and trying to maximize $$$ almost all of this complexity, all these choices, would go away.

Thanks for all the info on this! It's a lot to read through!

A sieve is definitely too much money for me to buy, and a bit too complex for me to sort through at this moment. I enjoy doing those types of DIY projects, but I simply don't have the time to do it right now. This pond build is already taking up way too much of my time (as with any project I tackle, I'm way overbudget in both time and money!). I think the only reasonable thing for me to do is to do a pre-filter. If I am unhappy with it, I could always come back and do something else at a later date when I have more money and time to throw at it.

Also, the TPR that you had mentioned in my other thread. Now that I've decided to get the 4200gph pump instead of the originally planned 2000pgh pump, I really won't need to route my skimmer outflow into the waterfall. So, if I just took the hose from the skimmer pump and routed it back into the pond so that the water flow would form a bit of a vortex, would that basically accomplish the TPR?

 

[max384]

The cheapest I suppose is that you could also just fill up a container full of sponges and foam pads and this would work for ya as a particulate filter, but you would have to clean more often, that is whenever you can get to it.

The thread... Mechanical filtration choices disucssion (https://www.gardenpondforum.com/threads/mechanical-filtration-choices-discussion.12085/) ... talks about all sorts of options.

Since you are looking into burying it, then you could look into a gravity flow sieve since these sieves must be roughly below the pond's water level. My personal preference are sieves, but a sieve filter is the second most expensive particulate filter (around $700~1,500) unless you DIY it. There are all sorts of retail gravity flow sieves. DIY Concrete Sieve thread (http://www.koiphen.com/forums/showthread.php?135723-Concrete-Sieve) is about the cheapest DIY sieve I have seen, which is a gravity flow fed sieve that can be placed before the pump. However, this is a no pressure filter, which means the pump is restricted according to how much water flows into the gravity flow sieve.

To better understand how a sieve functions, then check out the thread, A brief explanation of Wedge Wire Sieve Filters (http://www.koiphen.com/forums/showt...breif-explanation-of-Wedge-Wire-Sieve-Filters)

There is also a vacuum pressurized Zakki Sieve (http://www.koiphen.com/forums/showthread.php?136154-Zakki-Filtration-System-Video&highlight=) that can be placed before the pump, which means you do not have the flow restrictions of a gravity flow sieve and the bottom drain pipe is much less likely to get clogged. This is what I use along with a very small bottom drain with just a 1" pipe. The sucker sucks in leaves and all sorts of big junk.

For fines filtration + bio-filter hybrid, look into possibly making your bio-filter a trickle K1 bio-filter + moving bed hybrid.... the below video talks about this the best. The sticky bio-film on the media actually works incredibly well for fines filtration, and, to clean it, you simply do a bypass so to stop pump flow, fill the bucket, turn on air stone to highly boil the media, do this for a hour or so, drain the bucket, now good to go, drain the bucket, resume operations as a trickle filter.

Instead of a centrifugal filter (http://www.waterco.com.au/component...ucts/filters/multicyclone-centrifugal-filters) for fine particulate filtration, then you can use the trickle+move hybrid filter or quilt batting or a sand & gravel filter or an aquaponic deep water culture (DWC) grow bed. A DWC is like one huge settlement chamber where you only grow plants and the high sedimentation period is what acts like a fines filtration, even though there is a small amount of aeration in it. I have not found a good DWC video just yet, also called a raft grow bed, but there are plenty of videos about them on the YouTube. The DWC would be placed after your primary large particulate filter.


So.... It all depends on how much space you want to sacrifice and how much money you want to spend and how much you want to DIY.

You have MANY choices... which many of the choices will be removed due to: 1) costing too much ; 2) you do not want to sacrifice the space foot print.

Wow. Thanks for all the filter option info. I still need to read through that mechanical filter thread. I'm most strongly leaning toward the mechanical filter route at this point. But I still need to go through your links. Thanks!

 

[Waterbug]

Able to post pics again. Pond as a settlement tank.

 

[Waterbug]

Also, the TPR that you had mentioned in my other thread. Now that I've decided to get the 4200gph pump instead of the originally planned 2000pgh pump, I really won't need to route my skimmer outflow into the waterfall. So, if I just took the hose from the skimmer pump and routed it back into the pond so that the water flow would form a bit of a vortex, would that basically accomplish the TPR?

Yes, that's a common setup...skimmer to TPRs.