Hello, all! Oh, and I need info...

[James5]

Hello, folks! My name is James and I am a resident of Freeport, Il. Working on a pond I guess I'm a little confused about about a couple different things so I thought I would go to the best place for advice.

First, a quick rundown on the pond's background. A year and a half ago I bought my first home and the following spring I set about putting in a koi pond since I had wanted one for years. The result was a roughly thousand gallon pond, rectangle in shape, pumped and filtered by a bundle I bought from Amazon. The pond had multiple issues, all of which stemmed from the fact that it was a DIY job by a complete amatuer. I decided last fall that come this summer I was going to rip it up and redo the whole thing. So a couple weeks I ripped the old pond out completely and started digging to make it much bigger. I am now at a point where my hole is roughly 16'x16', 3' deep with an area in center that is dug down to 4' deep. A new liner and underlayment are still in their packaging in my garage and I'm awaiting have stones delivered in a couple weeks to start putting it all together but I have a few issues/ questions I need resolved before I start working it all in.

First question has to do with bottom drains. My first pond just had a pump that sat at the bottom of the pond. Orginally planned on doing the same for the new pond just with a more powerful pump. However, the more I read and research the more I am convinced that a bottom drain is the way to go. Actually installing the drain is not the issue as there are plenty of videos and how-to's pages out there. Question that I have is: then what? How does a pump fit into having the bottom drain? Where is it positioned? Etc etc?

Next is the skimmer. Same kind of questions. I know how to install the skimmer but then what? Does a pump have to be attached to that (I'm assuming) and does there have to be a line running from the skimmer to somewhere?

The whole underlayer, liner, stone work and all that I understand perfectly fine but a lot of the plumbing stuff still confuses me. Any advice or information would be very, very helpful.

Thanx,
James

 

[sissy]

welcome and sorry can't help you with a bottom drain or a skimmer since i neither but some on here may be able to help you I'm sure .I did my pond and cutting a hole in the liner like that was just to scary for me .I have koi and they are a bit of a hassle and get very large

 

[Waterbug]

There are different ways. It is first best imo to get some basic understanding and then you'll be able to make an informed choice. Actually with the basics you'll already know the answers.

Bottom drain
There are 4 components to a bottom drain (BD) system: drain, pump, filter, tangential pond returns (TPR). Missing any one component renders the system worthless. Each component can vary a great deal. For example TPRs could be replaced with a pool brush and you out there every few days pushing crap to the drain instead of a pump doing it for you. A vacuum could be used instead of an actual drain, etc. My point is that the 4 components should be looked at as function rather than as pieces of hardware.

Next thing to understand is the BD purpose. Different people, different purposes. If you're looking to have some nice big Koi you probably want to get poo out of the pond as quickly as possible and so the best filter choice would be a gravity fed sieve filter. That would answer your first question about pump position, you'd want the pump after the filter (or in the filter).

If you want a BD just to making cleaning the pond bottom a couple of times a year easier you don't need a pump at all. The pond would act as a settling chamber, you would brush debris to the drain, open a valve for a short time so the pond flushed away the debris. Then you'd refill, so the pump component of the BD system is provided by the water company.

There's a third way where the pump is connected directly to the BD and pulls debris through the pipe, chops up the debris and spits the crap frappe right back into the pond or into a filter that can't possibly remove the now fine particles. This is how people who don't like to research do their first BD.

Skimmer
A pond can be designed to overflow and the overflow point becomes a skimmer, much better imo than skimmers with flaps. With a regular skimmer the pond also "overflows" into the skimmer, but most people don't notice that small point.

In both cases there is a reservoir behind the skimmer, can be very small, but a reservoir none the less. An external pump is connected to that reservoir or a submerged pump is placed inside the reservoir. The pump can't be so big as to drain the reservoir before water from the pump can make it's circuit back to the skimmer.

Side note...
I've read several threads on Koiphen of people in your position who were exactly where you are in your project. If you wanted the best info on the planet you could pick one or two of those and experience the entire process through their eyes (soon to be your eyes). I'm talking about threads that are several years old so you see the whole experience. Some have the best Koi pond builders in the US contributing. You will read people posting questions at the same level you have posted and see people saying "Stop right now" "Put down the shovel" and then explain the issues. Some people do stop, listen, learn and have good outcomes. Some people don't and the out come isn't as good. In one case the pond split when filled and thousands of additional dollars had to be spent to sort of hold it together, but still isn't right. All that builder had to do was be willing to listen and spend maybe $100 for extra rebar and concrete and instead of tears could have had smiles.

In that not so good outcome thread there was a fair amount of discussion at the end from people who saw the problem coming, warned the poster, and left the thread when clear the poster thought she knew better. Everyone says they want to know stuff, but then get very defensive. Those posters felt bad that they hadn't been more vocal in their warnings. Are hard feelings up front worth saved less hardship later? Tough question. Many pond forums are more of a cheerleader type deal, people supporting other people, rather than worrying about whether something is built poorly. You get can a lot of support as you're driving off the cliff.

So going the tough love route...the questions you're asking tells me you should stop and do a lot more research. Your choice, obviously...not my pond.

 

[JohnHuff]

First, welcome to the forum. That's a mighty huge pond!

How does a pump fit into having the bottom drain? Where is it positioned? Etc etc?

If you have a bottom drain, then your pump will external and won't be sitting in a pond. Your pump will sit outside of the pond and it will draw water from the bottom drain. Your filtering system will also be outside of the pond, it can go either before or after the pump, or both.

You can install a skimmer as well, but it can't be in series with the BD since it basically just another drain, but one that sits at water level. It will need another pump, either in it or after it.

WB's post above has some merit, you can check out some of those pond builds to see what works for a pond like yours. But it can be very simple too. I've seen a guy build a pond as big as yours with two bottom drains leading to a single DIY filter with mats only as the media, and there are guys who'll spend ten thousand dollars on multiple filtration units and get the similar results. Now, what other specific questions do you have?

 

[j.w]

James

 

[ididntdoit99]

Just a little info from my experience i rebuilt my pond this spring, and was toying with the idea of a bottom drain and skimmer. I ended up just doing the skimmer and skipped the bottom drain.

Again, in my experience, the skimmer pretty much deleted the need for the bottom drain. I have lots of trees in my yard, and while its only been a few months since the rebuild, i have lots of blossoms and helicopters falling in the spring, and the skimmer took care of them before they hit the bottom.

I can't say for sure... but i can see the bottom of my pond, and i have little debris in it thus far. My setup is a bar at one end of the pond that has holes drilled in it, (on the left in the picture, skimmer is on the right) making a current that pushes stuff toward the skimmer, and then the skimmer pulling it in.

 

[James5]

For the most my questions are being answered and it is greatly appreciated. I am by no means one to get defensive since I want to build it right the first time so every season isn't a rebuild for me. I know some but not alot. Hence why I'm here

For folks thoughts, however, here is my plan for my DIY filter:

I bought three large plastic trash cans that will be inside my garage (my pond site is next to my garage). I put a hole in the bottom of "Can A" for the inlet then a hole at the top and PVC tubing at a 45 degree angle to the bottom of "Can B" and so on. My idea is to put media in each trash can and then an outlet at the top of "Can C" for it to flow to the water fall.

Seems like a sound idea?

Aaaaaand back to the bottom drain question. If the entire theory regarding bottom drains is to pull all the "junk" from the bottom floor of the pond to the drain then would it not serve the same function to simply make a recessed area at the deepest part just large enough to hold a pump? Yes or no?

 

[Waterbug]

I bought three large plastic trash cans that will be inside my garage (my pond site is next to my garage). I put a hole in the bottom of "Can A" for the inlet then a hole at the top and PVC tubing at a 45 degree angle to the bottom of "Can B" and so on. My idea is to put media in each trash can and then an outlet at the top of "Can C" for it to flow to the water fall.

Works great right up until the container splits. Been there. Lots of people say the work forever. Hope you're in the lucky group.

Aaaaaand back to the bottom drain question. If the entire theory regarding bottom drains is to pull all the "junk" from the bottom floor of the pond to the drain then would it not serve the same function to simply make a recessed area at the deepest part just large enough to hold a pump? Yes or no?

Nope. BD don't pull junk, TPRs push junk. And what would be the point of the pump grinding all the junk into baby food?

These things you are saying scare me. Good luck.

 

[James5]

Waterbug! Preach to me! :razz:

I've been leaning toward going with a pump connected to the bottom drain mostly because the gravity flow dealy kind of confuses me. I understand the physics of the water going down the drain but would the water not stop once it reached the quivalent of the water level in the pond?

 

[Mucky_Waters]

I understand the physics of the water going down the drain but would the water not stop once it reached the quivalent of the water level in the pond?

It would if you stop the pump, but as long as you continue pumping water from your filter back to your pond you create an imbalance and the water will continue to flow.
I think the biggest merrit to a bottom drain is that you can use gentle gravity flow to move fish waste and debri to your filter system, rather then running all that muck through the blender (pump) and making it harder to filter out.
Think of it this way, rather than pumping dirty water to the filter, you are pumping already filtered water to the pond, and allowing gravity to draw the dirty water through the filter system.

 

[James5]

Oooohhhh ok! *click* it makes sense now.

Does incline play a factor in this?

Basically if I have a bottom gravity drain pulling water into my filtration system does have to be pumped out or can it just flow back via gravity again?

 

[Waterbug]

If you promise not to take my word for anything and check it out for yourself. I can point you to different web pages for different things. From there you'll have a couple of points of view a can do some additional research. The problem I have is I'll never know what kind of pond you want, that's in your head and it may change.

What kind of pond?
You said Koi pond. I assume you mean with actual Koi? Any goldfish? Some people call all ponds Koi ponds. How many Koi do you want? How much do you plan to spend on the fish?

Here's where bad info will kill you...
Somewhere you read the theory that bottom drains pull debris...with that bad info you made a logical, but untrue, deduction that a deep spot would collect debris. Well, it will, but when I'm talking about a BD system I mean one that keeps the entire pond bottom clear of debris, not one where every few days something happens to fall into the drain.

Then you put the pump down there because I'm guessing you're missing an overall picture of the entire purpose of all this. The purpose of a BD system is to get crap out of the pond as quickly as possible. They can be used for other things, but that is their function. Removing big stuff is easier than removing little stuff. Would a pump grinding up fish poo into dust be good or bad?

BD pulling myth...
I've read that thing about BD pulling debris many times, more so 10-15 years ago. People saying that haven't a clue what is going on. You won't read that in a serious forum.

History of mechanical filters..
What you described, the "recessed area", would be a settling tank. You'd be using the pond as a settling tank, which is fine is a person wants that kind of pond. Here's a picture I've posted many times.

This is a pond as a settling tank with a BD, Open the valve to flush.

Way back people did add settling tanks. Everyone thought they were cool as heck, everyone wanted one. They didn't work very well. So people made larger tanks, slower water, more settling. Still didn't work. Then the Vortex filter same along, cone shaped smooth bottom and swirled the water by angling the incoming water from the pump. Better, but not great. Today's BD systems are based on that Vortex idea and using the pond as the tank.

What you'll hear many places on the web is from people who learned about ponds 15-20 years ago and have been repeating the same stuff all this time in forums. I kid you not. A year or so ago I came back to pond forums after being away for about 10 years...same people saying the same thing. Amazing. Then you have people listening to that and repeating it over and over. Their pond works great and so there's no reason to learn new methods, which is fine for them. But it's a problem for people wanting to learn because they think they're getting modern methods.

Learn about water...
In the picture above if you threw a handful of glass marbles into the pond they would roll down the sides and into the drain. Perfect, exactly what you expect. Now throw in a handful of polystyrene marbles. What would happen? OK, no one would know, I had to look it up. They would sink because they're slightly more dense than water. Next throw in a handful of wood marbles. What would happen? Of course they would float, duh.

OK, those polystyrene marbles, still sinking, slowly. So you now know they're heavier than water. While we're waiting for the polystyrene marbles to hit the bottom lets have a side bet on what is going to happen when they hit the bottom. Roll to the drain slowly? I'll bet you're not really sure. You be sure about the wood marbles. And there's the thing, it's not a safe bet to apply your experience to systems you have less experience with. Just a little bit of research will teach you the answer, but if you assume a logical assumption is true you'll never do the research.

OK, 10 minutes later they're on the bottom, ready to start rolling toward the drain...waiting, waiting, hey they aren't moving! Why? Now that they hit the bottom there's friction. The difference in density between the polystyrene and the water isn't enough to over come that friction, so the polystyrene marbles just stick there. The glass marbles would be dense enough to roll...unless the slope was very slight and then even they wouldn't go to the drain.

Virtually all material in the pond that we want out is very close to the density of water. Gravity has almost no effect. Slope sides have almost no effect at least from gravity.

If you look at an old time BD you'll see maybe 3-6" around the drain that is clear. The current being pulled disperses and drops so fast it has no real effect on settled debris. BDs don't pull debris.

Current moves debris...
Wind is weaker the closer to the ground you get. Toss a handful of dry dirt in the air and even a slight breeze will move it many feet. While on the ground the same breeze will have no effect. All this light as water stuff can be moved with even a small amount of water current in the same way. Pond keepers learned that from Vortex filters (I mean pond people, science has know it, and all this stuff, for a long time). That's when TPRs came into use. Google them.

 

[James5]

At this point I have theories and ideas but no beliefs- hence why I'm in the research stage.

So, if I'm reading you correctly, TPRs are more important than sloped sides or are those still considered essential?

In terms of flow from gravity, is it then possible to run the water via gravity into the filtration unit and allow gravity to also then carry it back to the waterfall box? By that I mean the height of the exhaust from the filtration is higher than the waterfall box so the tubing connecting the two is at a decline.

 

[Waterbug]

I've been leaning toward going with a pump connected to the bottom drain mostly because the gravity flow dealy kind of confuses me. I understand the physics of the water going down the drain but would the water not stop once it reached the quivalent of the water level in the pond?

It is confusing. These are not systems most human have any experience with. If they don't confuse you then you don't understand them. Yeah, wrap your head around that Yogi Berra perl.

I sure have to stop and think hard every time.

Just to add to Mucky's good explanation....

Ignoring the pink/white pipe and the tiny pond and how I spell reservoir when I don't have a spell checker... The pump is off. The water in the vertical pipe does indeed stop at the same level as the pond just as you thought.

Now turn on the pump...water starts moving out of the reservoir and into the pond. Water level goes up in the pond...and also up the vertical pipe and exits the pipe into the reservoir. That's a gravity feed filter, well, it would be if a filter is added. The filter to add is a sieve filter. Google it. Cetus Sieve from Evolution Aqua is top of the line and is $1200. There is an easy way to make one for very little money. That's another subject.

As you can see the pump can be submerged or I could have moved it outside the the reservoir if I wanted to use an external pump. Either works.

The other thing you may notice is the pump's outflow into the pond, not to a waterfall. That's the TPR which creates a current to rotate all the water in the pond. Current will be fastest around the outer sides and almost nothing in the very center, like a tornado, sweeping debris to the drain. The height of the TRR should be like 1.5' above the bottom (not what the picture looks like) and there should probably be 2 for a 16'x16' pond.

 

[Waterbug]

So, if I'm reading you correctly, TPRs are more important than sloped sides or are those still considered essential?

Not more important...essential. TPRs are as important as the hole in the bottom of the pond.

People do have BD systems in flat bottom ponds. Here's a mind blower....the pond bottom can be a hill with the drain at the top of the hill and it would still work...that's the power of current on matter near the density of water, just like a tornado lifts...but that would take a lot more current so no one in their right mind would build it that way.

Current best practice imo based on other builders who are better than me, is a slight depression, 6" down from the sides to the drain, bowl shaped, with it flat at a 1' radius around the drain.

In terms of flow from gravity, is it then possible to run the water via gravity into the filtration unit and allow gravity to also then carry it back to the waterfall box? By that I mean the height of the exhaust from the filtration is higher than the waterfall box so the tubing connecting the two is at a decline.

Maybe I didn't flow...this sounds like a perpetual motion machine? There has to be a pump some place.

Water doesn't care whether a pipe declines or ascends, it will seek level either way without a pump.