A common question people ask is “Do I need a pump for my pond?”
It is possible to create a pond that doesn’t require a pump. After all in nature ponds don’t have pumps. But of course in nature most ponds are receiving water changes through runoff or natural springs.
They also have a large amount of sludge at the bottom which is a breeding ground for beneficial bacteria and enzymes. The bacteria and the enzymes work to purify the water.
There are also generally lots of plants along the margins of the pond and growing within the pond itself. These work to reduce the nutrient load in the pond.
Quite often ponds in nature will have periods where they have an algae bloom. This is caused by excess nutrients in the water. This generally occurs after heavy rain or during season changes.
A pond in nature is generally nice and deep. This helps maintain a more stable water temperature.
So if we can replicate these things it’s quite possible to create a pond without a pump.
Replicating water changes.
The easiest way to do this is if you connect a down pipe or two to your pond. This way every time there’s a down pour new water will flush the pond system.
Of course make sure that you have an overflow in place so that the excess water can be returned to the stormwater system.
If the pond is small it may be possible or easier to manually top up the pond. Remember never use water direct from the tap if your on mains water.
Tap water from the mains contains chlorine. Chlorine will kill the good bacteria living within the pond.
When you need to use tap water there are a couple of options:
- Treat it with a chlorine neutraliser.
- Allow the water to sit for at least 48hrs. This will allow the chlorine to evaporate.
Often it can be tempting to place a pond in an area that is a naturally wet area or a low depression. This is fine, just understand that runoff will generally pick up excess nutrients and debris in its travels.
While the water inflow can be a welcome addition to the pond the excess nutrients are not! Expect to see an outbreak of algae in this situation.
Algae in its self is not a bad thing it’s all very natural! It just looks terrible.
Eventually the good bacteria will rebalance the pond and the algae should dissipate.
Pond sludge is made up of all the waste that finds its way into the pond. This may be fish poo, dead leaves, dead algae or silt.
In a pond in nature this “pond sludge” is home to millions if not billions of beneficial bacteria and micro organisms processing this waste.
Pond sludge can be unsightly if the water is stirred up, but if left untouched you may not even notice it.
The beneficial bacteria living in this sludge are the workhorse of any healthy pond ecosystem.
All that debris in the bottom of the pond is slowly releasing ammonia into the pond. There is a type of bacteria that will convert the ammonia into nitrite. Then another helpful bacteria converts the nitrite to nitrate.
If you want to understand more about the nitrogen cycle in a pond you can read our article on the topic.
Nitrate in high levels will lead to algae blooms. The water change or turnover helps to dilute the nitrate levels.
Another awesome way to remove nitrate from the pond is plants! Lots and lots of plants!
If the beneficial bacteria is the workhorse of the system, then the plants are the guy holding the plough. The plants have a number of benefits:
- They will consume the nitrate in the water. Nitrate is the most common ingredient in plant food. Removing the nitrate robs algae of the nutrients it needs to grow. If your pond is in a low spot. Well planted areas through the runoff zone can help remove nutrients before the water reaches the pond.
- Plant roots will add more surface area within the pond. The more surface area that is constantly wet the better. Good bacteria will colonise all constantly wet surfaces.
- They can shade the water. Floating plants like Lilly pads, duckweed and azolla float in the surface. This creates shade. The shade will help keep shallow water cooler. This is great as algae likes warm sunny water. So again these plants can occupy an area that algae would otherwise become a potential problem.
- Well they just make the pond look good. A well planted pond blends into the landscape so much better, than one without plants.
Rocks and pebbles are an excellent way of adding extra surface area for beneficial bacteria. If you have no pump over time the sludge will build up. This will cover the rocks, so there’s no need to buy pretty rocks at least not for the bottom of the pond.
Rocks on the edges and walls create great habitat for frogs, shrimp etc. Rocks also can be formed to make natural pots that will be used to grow marginal plants around the edges of the pond.
Smaller pebbles are best for the bottom of the pond. Larger rocks for the walls and protruding from the water.
A nice balance of rocks, plants and even some drift wood can really make your pond look amazing!!
The depth of a pond with no pump should be at least 60cm or more. Deeper water will stay cooler, again this helps reduce algae growth.
A deeper pond will allow the sludge to form a layer on the bottom without it being visible.
I’ve found most councils don’t need a permit or fencing requirements for “untreated water features”. Which a pond falls into.
Treated water includes pools and spas. But ponds are currently exempt.
Of course make sure you check your local council website for rules and regulations in your area.
Mosquitos don’t like deep water! A pond without a pump may become a mosquito magnet if it’s too shallow.
Another tip related to depth is allow an area where the bank slopes gently out of the water. This is for any animals that fall in the water.
If a rabbit was to fall in the pond and was unable to escape it will drown. The dead rabbit will breakdown causing a huge spike in nutrients and a guaranteed algae bloom.
A pond with no pump should avoid having too many fish!
Fish will add what’s called a bio load to your pond. This basically means that they will produce waste. The waste (and fish breathing) will release extra ammonia.
The extra ammonia means you’ll need extra beneficial bacteria. In a pond with a pump the water circulation allows water to be constantly moving over, around and through those surfaces that are home to the bacteria.
In a pond without a pump this isn’t occurring anywhere near enough to sustain many fish! Especially messy fish like goldfish.
However If mosquitos are a concern you may need to add a few fish. If this is the case use small fish with low bio loads. Native fish like galaxias are great but sometimes hard to come by.
A small fish like white clouds will tolerate poor water conditions and is a mosquitos worst nightmare. These are very common in the aquarium trade.
If using a non-native fish like white clouds ensure that there is no possibility of escape into local waterways.
So it is possible to have a pond without a pump. There is less room for error though. You really need to create the perfect balance for it to work well. I would always recommend having a pump.
Quite often people avoid adding a pump due to the cost of getting electricity to the area where the pond is.
You’ll be surprised just how far you can extend a low voltage pond pump without the need of an electrician.
Most 24v pumps can be extended up to 70m from a power source and 12v pumps 30m. Certainly something to look into if thats a concern of yours.
Another reason for not adding a pump is people worry about the cost to run one. If that’s you check out the article – how much will my pond pump cost to run?
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