Bottom drain, plumbing and pump advise needed

[pecan]

Hello everyone!

Since we decided to stay in our house I have been thinking about re-doing my pond. Not any time really soon. First I want to install a small pond on the other side of the patio. Once it is up and running it will provide a temporary place for my kio so I can re-do the larger pond. The smaller pond wont go in till next year, then the re-do maybe the year after that, so I am just planning ahead.

The main thing I want to do with my big pond is remove the shelves, install a bottom drain and go deeper. It is currently 21' x 17' x 40" deep.

Right now I have 2 pumps in the pump elevated from the bottom feeding two skippy filters that feed a small bog then down the falls back into the pond. I suspect I have about 6000 GPH moving all the time.

I understand the install of the bottom drain. But the plumbing from there is what has me confused. I am no plumber and can't really wrap my head around any of it. I am not sure how the water flows up-hill etc. I am not sure where I should place my pumps and how to clean out the settling tank.

I have spent a long time googling it and can not find very detailed information on the pump placement etc. So I drew a little picture of what appears to be the way to do it. But I could be completely wrong.

Here is the picture and some of my questions.

1. Does the pump go in the settling chamber?
2. Can the clean out pipe go up at an angle like that or does it need to flow down?
3. How many bottom drains do I need for the new pond (approximately 7000 - 8000 gallon pond)
4. In general what is wrong or right about this design, what would you do differently. Keeping in mind I want as little plumbing involved as possible to avoid future issues with leaking.

Thank you everyone for all your help as always!

 

[randythawkins]

Pond and Settlement Chamber (SC) sit at the same level with the pipe from the pond feeding into the side of the SC. When water is added to the pond it will also flow in to the SC and both will top off at the same level. A pump pulls from the SC drawing it down and, as that happens, water from the pond flows into the SC as it attempts to maintain a consistent water level. Try this mental example...take an empty milk jug and start filling it with water from the sink faucet. If you look inside the jug as it fills up to the bottom of the handle the water will start to fill up not only the jug part but also the inside of the handle. It is all connected so the water levels itself out in all components. Same thing with the pond, SC, and bottom drain pipe connection.

In your drawing, as long as the end of the clean-out is below pond water level, when you open the valve water will run up the clean-out pipe and out the end. Now, how much does this depends upon the vertical distance between pond water level and the clean-out pipe opening.

 

[crsublette]

Yep, Randy covered it quite well.

Also, rather than angling up the clean-up pipe, some folk have something like a bucket or container of some type below the SC to catch the waste water. When getting ready to flush the SC, you put a heavy duty sump-pump, that is capable of pumping very dirty and trashy water, to pump the water out of the container and then it goes into a garden or something.

 

[gardengimp]

Pecan, do you know about the Aqua Art Retro Bottom Drain? Add a bottom drain to an existing pond without punching a hole in the bottom of the liner.

 

[Mucky_Waters]

Most often ponds with bottom drains have a filter "pit", which is simply a below water level dug-out area where the settling chamber, pump and filters go. As far as pump placement, it could go in the SC, but usually you'll find them after.
The outlet end of the drain line in the SC needs to be below the water level. You'll find that in a flat bottom settling chamber it will be hard to get all the debris out, an you will find that you'll have to stir it up a bit as it's draining. An easier solution is to buy a cone shaped tank.
I think two 4" bottom drains is what is recommended for a pond that size.
Have you considered buying a sieve? They are much more effective at filtering and the have a smaller foot print. If Waterbug was here he'd recommend the addition of TPRs in the pond, and I think with the size of your pond I would have to agree.
I think you are approaching the potential leak problem the wrong way. Rather than trying to have as little plumbing as possible and hoping it doesn't leak, you should be prepared to put in as much plumbing as is necessary, and MAKE DAM SURE it doesn't leak.

 

[pecan]

It looks like a sieve is a mechanical filter? Do you use it in place of the settlement take or inline before or after the settlement?

Currently I am running my pumps to 175 gallons worth of skippies that overflow into a small plant bog and back down the water fall. I have had low maintenance and clear water all year. The only reason I want to add the bottom drain is so I don't have to muck out the bottom of the pond like I do currently. But as far as clean water with good levels this year has been great. My pond is currently around 5000 gallons.

Also note I am in a zone 7 with a frost line of 30". My pond at the most has only ever had about 10" of ice in the last two winters. Not sure how this impacts all the plumbing. Currently I just pull my hoses in the winter as none are buried, shut off the pumps and leave them in the pond at about 2' deep.

 

[Mucky_Waters]

What does a sieve do?

Pond sieves are usually installed directly after bottom drains, where a SC would normally be installed, and, as the name implies" they "sieve" (or strain) the pond water through a fine stainless steel micro screen. The water from the bottom drain flows over and through the sloping micro screen. As debris is captured on the sieve the water pushes it down the sloping sieve towards a discharge port, so in effect the sieve is constantly being flushed clean automatically by the incoming water where it accumulates at the bottom of the screen next to the discharge port.
Sieves are much more effective at removing debris than settling chambers and way easier to clean, but they are a little pricey, and they are not as friendly to small fish that might get sucked through the bottom drain.
Do some searches on Google and Youtube, they work slick, but as I said they are a little pricey, but well worth the money for someone with as large a pond as yours.

 

[pecan]

Thanks Mucky! I will look into that. I suspect with two bottom drains I would need two sieves and a pump in each.

 

[crsublette]

Not necessarily. It all depends on how the plumbing is done and this will determine what pumps you need.

If all of the filtration is going to be below pond water level, then you can just have the exiting water from multiple sieves gravity flow into the skippy's top and have a single pump pulling from the skippy's bottom.

If this is going to be a retro-fit drain and you do not cut through the liner so that all of the plumbing remains below water level, then it will have to be a sunction fed filtration system.

Here is a good thread that might be interesting to ya, mechanical filtration choices discussion.

The problem with a sunction fed filtration systems is that you will need an enclosed pre-filter to catch the big debris, such as leaves or twigs before it clogs up your pump and also any debris that does manage to go through the pump will get chopped up into smaller pieces. There is only one sieve, that I am aware of, that is truely a suction-side sieve, called the Zakki Sieve and talked about in that discussion thread.

Actually, the entire purpose of a settlement chamber is to seperate the big debris before the big debris clogs up your pump or clogs up your other filtration. Settlement chambers is a pre-filter for gravity flow systems. Leaf pots or baskets are the pre-filters used for pump fed filtration systems.

Give me a moment here and, in that discussion thread above, I will hyperlink a very excellent DIY big debris pre-filter so that you can capture the big debris before it clogs up the pump.

 

[crsublette]

And here are the examples of the DIY big debris pre-filters at post#50 in that discussion thread.

 

[crsublette]

All of the debris will not simply be pulled to the drain. There is a suction sphere of influence around the drain where the trash will get pulled toward the drain. Trash further away from the drain might eventually make it to the drain due to water movement and the fish moving the water to push the debris closer to the drain.

This is where "pond returns" and aerators come into the picture. When you get a drain, get one that has the option for an air diffuser to be mounted on it or has one on it. The aeration actually drives water movement, in a vertical circular motion, so that debris from further away will make it faster toward the drain. "Pond returns" are simply like water jets, much like in a swiming pool, except they are angled in a particular direction so to help encourage even more water movement to create a vortex water flow that brings the debris closer to the drain.

Here is a good thread that will help you better understand. Understanding currents within a pond obtain the idea of a self cleaning pond.

Waterfalls also contribute to the water movement to help bring the debris closer to the drain.

Again, you do not nessarily need pond returns nor an air diffusor, but it sure does help.

 

[crsublette]

Howdy Pecan, I've been thinking more on this so to make sure you have a good picture all around of how things operate before making any purchasing decisions.

I hope your plumbing question was answered.

Also, you can do a Leak Test on your plumbing before you cover it up and put water in it. After all the plumbing is finished and before you connect the bottom drain, cap all of the plumbing. Then, tap an air chuck connector with a valve to a cap that can be tightly screwed or glued on the pipe. Then, us an air compressor to slowly increase the pressure to around 10~20 psi. Turn the valve closed to hold the air pressure in the pipe. Wait 24 hours or a couple days. Come back to check if you lost any air pressure. There will be flucations of the pressure throughout the day due to the weather heating up and cooling the pipe, but this variation should only be around +/-3 psi points. Come back to check on the gauge at the same time you took your initial reading. If the psi gauge reads significantly lower compared to your initial reading, then this means there is a leak somewhere.

Also, use sweeping 90 degree elbows. There are two types of 90 degree elbows, that is a hard 90 and a sweeping 90. The hard 90 is the typical 90 that you see that looks like a sharp elbow. A sweeping 90 is a 90 that is elongated and not sharp at all. You can also form a sweeping 90 by connecting two 45 degree elbows together. Sweeping 90s have a much lower friction loss rating when compared to a hard 90. Friction loss is the resistance water flow encounters as it is traveling through pipe, and the accumulation of this resistance does reduce your pump's flow rate. Valves and pipe size reducers also significantly add to friction loss. This is why it is better to use bigger pipe at the beginning so to significantly reduce this friction loss. There will always be this friction loss so all we can do is reduce those choke points, that is where friction loss is created. A sweeping 90 degree, or also two 45 elbows, have a much lower friction loss rating when compared to a hard 90 elbow.

 

[crsublette]

First, Pecan, I think you need to decide on a budget and what type of area foot print you want your filtration to consume. Your budget and desired area foot print will determine your options.

To further clarify, as others have mentioned above, sieves substitute settlement chambers (SC). You can have both a SC and sieve, but this is quite redundant and only necessary if you want to try to save any critters that get sucked in the drain.


source thread: Filter Conversion -- Thinking about sieve, maybe?

• AquaForte Compact Sieve II (250 micron, pump fed on outlet side of pump, gravity return out of sieve, 4,000gph max flow). Due to gravity return out of sieve, must be above pond water level unless an extra pump or airlift is used at the end of the filtraiton circuit.
• AquaForte Ultra Sieve III (300micron, gravity fed into sieve, gravity return out of sieve, 7900gph max flow). Due to gravity return out of sieve, must be above pond water level unless an extra pump or airlift is used at the end of the filtraiton circuit.
• Zakki Sieve (250micron, pump fed on sunction side of pump, pressurized return out of sieve, 1500gph minimum require flow to operate, 4500gph max flow, ). 80% of this filter can be under pond water level without an extra pump.

Cetus sieve is also a popular one as well, but I never have cared for it due to its area foot print and price.


Here is a video about construction and cleaning process of the Cetus Sieve. You will notice why it is simply just marketing talk by suggesting these sieves are "self-cleaning".

[video]

To help clarify the differences between a suction fed sieve and a gravity fed sieve, here is a good video. (source thread: Zakki filtration system video)

[video]

Also, to see how a suction fed sieve operates in real time and how it flushes, here is a good video. Also shown in the video is the polishing filter, the MC50 (also called the MC16). (source thread: Zakki filtration system video)

[video]

I am a big pusher of sieves since they do not require anywhere near the same sacrifice to area foot print as required by settlement chambers and you lose less water when flushing the waste in a sieve when compared to a settlement chamber, but sieves are significantly more expensive.


I am just showing the options you have in case you are thinking about upgrading.


I think what you are thinking is perfectly fine with a settlement chamber and skippy as long as it gives you results and you are happy with it. :banana: :claphands:

 

[crsublette]

Here is some info about bottom drains, flow rate recommendations for all the sizes of bottom drains, how they are installed, and the "why's". One moment.


The first article below, "understanding pond bottom drains", explains well about the distance recommendations and suction limitations between drains, but this is not a concrete concept. I have seen drains work very well even when they are lined up next to each other, depending on how the pond is designed.

For pipe and drain sizes, you choose according to your desired flow rate.

3" max gravity flow rate of 1500~1800 gph
4" max gravity flow rate of 3000~3600 gph
2" max gravity flow rate of around 750 gph
1.5" max gravity flow rate of around 350 gph

Now, if it is a drain directly connected to a sunction-side sieve and pump, then the flow rates can be much higher than what is stated above the gravity flow rate, but friction loss will increase.


These are some articles and hyperlinks that PDF archives since they have significantly helped me in my project. I found it to be excellent reading material.

Understanding Pond Bottom Drains

Aerated bottom drains waste of money??

Bottom drain to filtration, the smartest addition any ponder can make

Flow from a 4" bottom drain

Installing a 4" bottom drain

Installing the Koi Village aerated bottom drain

Need help with bottom drain installation and filtration design

Small Bottom drain blues - Restricting the restrictions

Why have a bottom drain and skimmer?

 

[crsublette]

Thanks Mucky! I will look into that. 1) I suspect with two bottom drains I would need two sieves and a pump in each.

1) I suspect with two bottom drains

So, for you wanting to do a flow rate of 6,000gph, my post above explains why you should have at least two 4" bottom drains.

Only reduce the pipe size once it reaches your filtration system. Do not reduce the 4" pipe size before it reaches your filtration system. If you do, then this might increase the likeliliness the pipe will clog.