Same water feature as above in fall of 2014
Building Natural Ponds
This blog post is the second most popular post ever on this site. Lots of people comment and are interested in more information about building natural ponds, so I have started a public Face Book Group to make it easier for people to discuss this hot topic. Please join the group at https://www.facebook.com/groups/1760349757565562/
Author’s pond at Aspen Grove Gardens (1 st year)
About 7 years ago I started developing various water features, both garden ponds and water falls. As part of my research I found consistent comments like the following: you can’t make a natural pond using a pond liner without pumps and filters. The use of the word ‘natural’ here refers to the pond filtration system, not the esthetic look of the pond. I’ll deal with esthetics in a future post on how to build ponds.
In a natural pond the water, soil, plants, and animals all live in harmony. No one comes along to clean the pond or to aerate it. There is no big man-made filtration system that keeps the water clean. The common advice is that a pond liner is artificial and a pond built with it will never reach a natural state where the water, plants, and animals live in harmony the way they do in a natural pond. If you don’t filter such an unnatural pond it will become full of algae and the water will be dirty and smelly. The only way to have a pond with a liner is to add aeration and filtration.
Is this really true? Do you need pumps and filters to provide artificial pond filtration?
Pond Pumps and Pond Filters
courtesy to : www.gardenmyths.com/pond-pumps-filters/
By Robert Pavlis on August 28, 2013
Beneficial Pond Bacteria – A Waste of Money
By Robert Pavlis on October 27, 2016
Water Feature Myth
The above information should give you some background to understand both natural and man-made ponds. If you think about it for a while you will realize that a properly designed pond, with enough pond plants and homes for microbes, should work just as well as a natural pond. When I was planning to build my ponds I spent a lot of time trying to find a reference for a man-made pond that worked without pumps and filters – I found none. Every reference I found said that such a pond will not work.
I set out to prove the experts wrong.
The following is not the result of good research or the opinions of experts. It is the result of my experience with two ponds over a 6 year period. In this blog I am not describing how to make a pond but I will do that in another blog entry–some day. I will provide the key points to consider.
Based on the information above, a pond design needs two things which are lacking in most designs. It needs lots of pond plants. Plants will use up the excess nutrients and keep the algae in control. It also needs lots of little homes for microorganism – they will help keep the water clean.
The following are some key design decisions:
1) Wide planting shelves. My pond is 20 x 30 feet and about half of that area is in the form of planting shelves that are about 8 inches deep.
2) Soil is not used for the plants. Pond plants don’t need a substrate, except to hold them down, and the pond certainly does not need more nutrients from soil. The plants should be using the nutrients produced by the micro-organisms and not the nutrients in soil . Instead of soil, I use small rocks – 1/2 inch or so. I just use all the small rocks I collect as I make new flower beds. Don’t fertilize your plants.
3) Pond plants are not in pots. I just place them on the small rocks in the planting shelf. A larger rock on top holds them in place until they root.
4) The sides of the pond are lined with rocks adding more surface area for microbes.
5) A deep planting shelf (about 2 ft deep) is also present for waterlilies. It is important to cover 2/3 of the surface water to reduce light getting to algae.
6) Goldfish were added to feed the plants, and eat mosquito larvae . They are never fed. They grow quickly and breed regularly.
The garden pond in the pictures was built 5 years ago and it is only now that the planting shelves are starting to be full of plants. Wild bull rushes seeded themselves the second year. Irises have been added and are spreading. The pond has never been drained, and the bottom is never cleaned. It has no pump and no filter. Wind is the only thing that might provide some aeration as it ripples across the surface of the water. There are several large trees around the pond that add fall leaf drop – which is left to settle in the pond.
For the first 4 years the pond plants increased in number each year. During this time, I did have string algae, but it mostly had a spring bloom and by mid summer it was under control. The water was very green showing the presence of lots of one celled algae, but the water was clean, and it did not smell. The fish that were added the first year did not over winter but since year two they have overwintered and keep breeding. Herons and racoons help to keep numbers in check.
From a naturists point of view the pond is very healthy with lots of frogs and dragon flies breeding each year. Larger mammals, including deer use it as a water source.
It is now nearing the end of summer 2013 and the pond has been extremely clean–much clearer than the picture below from 2012. In fact it is too clean. You can now see the pond liner in the deeper sections of the pond. There was no string algae this year and almost no one celled algae. It has been a strange year weather wise which may account for some of this, but I think it is mostly due to the fact that the planting shelves are now very full of hungry plants which are out-competing the algae.
After 5 years I conclude that aeration and filtration are ‘probably’ not required. I’ll need to wait another 5 years or so to be absolutely certain of this. It is possible that in a few more years the stuff at the bottom will overwhelm the pond and may need to be removed. I doubt it!
Building natural ponds face book group
What Happens in a Natural Pond?
In a natural pond animals (insects, fish, etc) eat, poop, sleep and die. Both the poop and dead animals add nutrients to the water. Some is added immediately, and some is added over time as the material is degraded by various micro-organisms.
Plants also add nutrients when they die. In fall all kinds of leaves and other dead plant material is blown into the pond, and as this material is decomposed by micro-organisms it also increases the nutrient level.
Algae is a plant that grows best with high light and high nutrient levels. When the nutrients get high enough, the algae takes over the pond and chokes everything else out.
Why does the algae not take over natural ponds? The answer is higher order pond plants (not including algae). Plants also use nutrients and as long as the plants in the pond use up the nutrients as fast as they are produced, algae has trouble getting a foot hold.
The secret to an algae fee pond is to control nutrient levels!
The other important part of a natural pond is the presence of micro-organisms. They are everywhere; in the soil, on rocks, and attached to plants. Think of these micro-organisms as the ‘cleaning machine’ of the pond. They take rotting, smelly animal and plant material and turn it into nutrients that plants and algae can use. The micro-organisms keep the water clean, and keep it from smelling.
A man-made pond made with a pond liner has no soil – so one source of micro-organisms is missing, especially if you keep cleaning the pond liner. Most ponds have few stones and few plants reducing the number of micro-organisms even further. Without microbes or filtration, the dead animals and plants just sit in the bottom, making the water cloudy and smelly. But it does not have to be this way – read on.
Controlling Nutrient Levels
There are a number of ways to control nutrient levels:
1) Don’t add too many fish. Too many fish results in too much fish poop. Koi poop more than gold fish.
2) Don’t feed fish. There are lots of natural things for the fish to eat. Adding extra food just adds more nutrients to the pond.
3) Have lots of living plants in the pond. With enough pond plants growing, they will remove the nutrients before the algae can grow.
Most man-made ponds are not designed to hold a lot of pond plants. Without the plants you need to add some type of mechanical filtration system.
Adding the pond liner to a water feature at Aspen Grove Gardens
The picture shows a pond at Aspen Grove Gardens during installation. The black pond liner is in the deep part and the planting shelves are covered in carpet (white/gray areas). The liner will be pulled up to cover the carpet.
Note the extensive size of the planting shelves compared to the total size of the pond.
Why Aerate a Water Feature?
A natural pond has no obvious aeration. There is no hidden pump creating air bubbles. So why is it needed in a man-made pond?
A poorly designed man-made pond does not have enough plants, and it does not have enough places for micro-organisms to live. As a result, dead stuff accumulates on the bottom. As this dead stuff starts to rot it uses up oxygen, and the water at the bottom becomes depleted in oxygen, which in turn causes anaerobic bacterial to grow. This type of bacterial loves the smelly mess and they thrive with low levels of oxygen. This seems like a good thing, and environmentally it is a good thing. The problem for us is that as they digest the rotting stuff, they make the water smell. We don’t like smelly ponds even if they are natural.
How do you get rid of the anaerobic bacteria? Simple, increase the level of oxygen by pumping air into the water.
Aeration is recommended for ponds so that they don’t smell and that works quite well. The problem is that without anaerobic bacteria, the sludge on the bottom degrades very slowly and so you also need to clean the bottom of the pond on a regular basis.
Think about this. Because you bought a pump and you aerate the water, you now need to do more work and clean the bottom.
Do Natural Ponds have Smelly Sludge at the Bottom?
Sure they do. It is quite normal to find this in a pond where a lot of animal or plant material falls into the water. You don’t normally smell it because the water is not stirred up enough to move the smells to the surface. Dig around with a shovel or step into it from a canoe and you’ll find the smell. The smelly sludge on the bottom is natural.
My man-made water features have sludge and anaerobic bacteria in the bottom. If I don’t disturb them, they degrade dead plant material, and produce nutrients for growing plants. In my ponds I don’t stir up the water so I don’t smell them.
Virtually every reference on building water features recommends some type of filtration system for a man-made pond. Why is this necessary?
As mentioned above, the lack of soil in the bottom of the pond and the lack of rocks and plants results in an environment that houses few micro-organisms when compared to a natural pond. The solution is to provide a man-made place for the microbes to live. Most filtration systems contain some type of surface for the micro-organisms to live on. This can be sand, wool, small pieces of plastic – it doesn’t really mater. What is important is that there is a lot of surface area. Microbes like to attach themselves to a surface and then ‘eat’ plant and animal bits as they float by in the water. So the filter replaces the natural places were microbes live–on soil, rocks and plants.
In nature the microbes live in the slime you find on rocks. It is healthy for a pond.
Water feature without a pond filter or pond pump 2012
tring algae is gone, but one celled algae is still making the water green in late summer. Note the number of plants in the water.
As plants grow and get larger, algae is almost non-existant.
Is Green Water Bad?
From an environmental point of view there is nothing wrong with water that contains algae. In a natural pond it might indicate that too much fertilizer has leached into the pond which is not good. But this is not usually a problem in a man-made garden pond. If your pond water is green with algae it is probably healthy.
You might not like the look – that is a different matter.
In Japan, garden ponds are treasured and it is common to buy a dye to color the pond water. Why do they do that? When the water is colored it reflects light much better. The shadows and reflections are considered to be very desirable. So next time someone comments about your green water, just tell them that you do it on purpose to better enjoy the reflections.
2- Natural filtration ( by Nature )
I was reading some gardening Facebook posts and a lady said she buys beneficial pond bacteria for her pond and adds them weekly. WOW! That was news to me. I’ve had a man-made pond for over 8 years that works just fine without added bacteria. I must be missing something important?
Truth be told – I smelled another gardening myth. Let’s have a look.
Beneficial pond bacteria for ponds – koi
Building Natural Ponds
Before I dig into this topic I’d like to add a shameless plug for my upcoming book, due out in May, 2017, called Building Natural Ponds – Create a Clean, Algae-free Pond without Pumps, Filters, or Chemicals.
Beneficial Pond Bacteria – The Rational
Algae can be a big problem in most man-made ponds. It grows when there is too much light, and too many nutrients, especially nitrogen and phosphorus. If you reduce the level of nutrients, algae will not grow as well. Problem solved.
So how do you reduce nutrient levels? The answer is really quite simple – you make sure that the pond contains a lot of beneficial bacteria. Beneficial pond bacteria also need nutrients to grow and they will out compete the algae for nutrients.
So far so good. This is a simple system that is known to work well.
To make this work you need to have enough beneficial bacteria. What is the best way to get them? From a manufacturers point of view that is obvious. Grow them, package them and sell them to pond owners in a fancy jar with a fancy name: ‘Beneficial’ pond bacteria.
Consider an average sized pond that is 10 x 10 x 2.5 ft, which is about 2,000 gallons. The first product I found on the internet was $30 US to treat this pond for 12 months. They also have the supper strength stuff at $60 US for 12 months. It’s not a lot of money, and if it is needed most pond people will pay this – every year.
What Are Beneficial Pond Bacteria?
There is no clear definition for this but essentially any mixture of bacteria that would decompose organic matter, use up nutrients and live in water would fit the bill.
The beneficial bacteria that are being sold are natural bacteria. We are not talking about expensive genetically modified bacteria. We are talking about the same bacteria that can be found in any natural pond. There are probably millions of species that would work just fine.
Adding Bacteria to The Pond
What happens when the beneficial bacteria are added to the pond? The bacteria will have a look at their environment and if they like it they will start to grow. As they grow, they consume nutrients and divide (ie make babies). In fact they can multiply very quickly – in the lab some bacteria double in number every 20 minutes.
As the number of bacteria increases, the amount of nutrients decrease. At some point there is not enough food for everyone and they start to die off.
It is important to understand that there will always be some food in a pond and so the bacteria never die out completely. Their numbers just get less. In fact the ones that die will provide nutrients for the ones that remain. Bacteria are cannibalistic.
Where Do Bacteria Come From?
Everywhere! They are in the air, water, soil, on plants, on fish, on fish food. Even before you add water for the first time to a new pond, the liner is covered with bacteria. The reason for washing your hands regularly is because they are covered with bacteria. Even wiping your kitchen counter with a disinfectant will not remove all the bacteria.
You can’t keep bacteria out of the pond.
Natural Bacteria in The Pond
The natural bacteria in your new pond do exactly the same thing as the ones you buy. They have a look around their environment. Some might not like being in water and they die. Some don’t like the temperature or pH and they either die or at least don’t multiply very much – they are waiting for conditions to improve.
A new pond has very few nutrients so bacteria don’t grow well for a while – but either does algae.
But in no time at all fish poop. Insects and birds drop organic mater in the water. It does not take long before the nutrient levels build up. As they do, bacteria start to flourish. You can see them as a coating of slime on plants, rocks and the pond liner. To you this is icky stuff, but to the pond this is a natural water purifier.
Why Do You Need To Add Bacteria?
Unless you do something to kill all of your natural bacteria you do NOT need to add more. Want proof? Have a look at Pond Pumps & Pond Filters. I put this man-made pond in 8 years ago. It has no filtration, no air pump and no chemicals. It does have a lot of plants and a lot of surface area (small rocks) for bacteria to live on.
Natural pond with no pumps, filters or added beneficial pond bacteria, by Robert Pavlis
You can do things to kill off your bacteria. If you add an algaecide, it will kill off bacteria (ref 3). Chemicals for adjusting pH will also harm your bacterial herd. If you recycle your pond water through a UV system you will kill bacteria.
Emptying your pond and scrubbing the sides to get it clean also kills your herd. This is recommended by many people and makes no sense at all. Why remove the slimy coating that is home to your natural water purification system?
If you did these things and killed your bacteria it might make sense to add purchased beneficial bacteria to get your bacteria numbers up quickly. Or you could just wait a day or two for them to start growing on their own.
Keep in mind that adding chemicals like copper based algaecides are long term problems. The copper does not go anywhere, unless you do a water change. As long as it is in the water it will affect the bacteria. Maybe this is one reason that companies who sell algaecides also sell beneficial bacteria and recommend you add them weekly. Their algaecide keeps killing off the bacteria so you have to keep buying more and more bacteria. Sounds like a good business!
The Commercial Bacteria Myth
In the words of one manufacturer “the addition of beneficial pond bacteria will render the pond clean and clear”. Is this true or is it a myth?
It may be true.
If for some reason you have killed off your bacterial herd, adding more from a jar will speed up the re-population of bacteria in your pond.
But this is only true if the following two factors are working in your favor.
Are The Purchased Bacteria Alive?
The bacteria in your purchased bottle need to be alive for them to work. You really don’t have an easy way to test this. One commercial source said that “live bacteria smell” and if the contents of your container doesn’t smell – they are dead. That is not very reliable. Besides dead rotting organic material (ie the bacteria) tends to smell!
Are The Bacteria Matched To Your Environment?
Every pond has a different environment with variations in things like water hardness, pH, temperature, existing microbes, nutrient levels, etc. The bacteria you add will only grow well if they like your environment. You can’t tell that by reading the label.
Natural vs Commercial Bacteria
The main argument for adding commercial bacteria is that the pond does not have enough natural ones. What would cause such a situation?
Other than added chemicals the two main reasons would be a lack of nutrients and a lack of substrate for bacteria to live on – the rocks and pond liner.
If your pond does not have enough nutrients for you native bacteria to grow and prosper, then it does not have an algae problem – there is no problem to fix and adding a commercial product is just a waste of money.
Substrate is the surface area where bacteria like to live. In commercial filtration systems this is usually some kind of sponge, or small pieces of plastic. Both of these provide a large surface area on which bacteria can colonize. The key here is the large surface area.
In a pond bacteria like to grow on the pond liner, on plants and on the surface of rocks. A properly designed pond will provide a large amount of surface area, usually in the form of small rocks.
If the pond has lots of places for bacteria to live then the native bacteria will already be living there. Adding more commercial bacteria will not increase the population.
It seems to me that if your pond lacks bacteria it means your pond does not have the environment needed by bacteria to live. Adding more from a jar is at best a short term solution.
Beneficial Pond Bacteria – A Waste of Money
Unless you do something to disturb your native bacterial herd I see absolutely no reason to add beneficial bacteria. The bacteria you already have are just as beneficial as the ones you can buy.
Aquascape sells a product that contains 1 billion bacteria per gram. One gram of healthy soil – the weight of a paperclip – can also contain 1 billion bacteria. If you feel the need to add bacteria just add a pinch of soil.
When I reviewed commercial products I noticed a lot of claims, but not a single piece of evidence to support the claims. There was not a single study to support the use of their products. However, a scientific study that I did find looked at adding a commercial bacterial product to ponds (ref 2) and found little difference in water quality between treated and untreated ponds.
Adding commercial bacteria to your pond to keep the water clear is a waste of money.
Other websites :
Koi pond natural filter build
Natural Filters - Best Filtration Systems for ponds and natural pools ᴴᴰ
KOI GROW BETTER IN ALL NATURAL POND? NO LINER/FILTER, LOW COST | BIOLOGICAL FISH KEEPING | BIO MUD
Natural Methods To Filter Your Pond Filters More Efficient - Water Lilies - Water Plants
Natural pond filter results after 2 weeks
Natural Bog Filter