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Introduction to Garden Pond Pumps
A pond pump lies at the heart of any successful pond system. It is the means by which life-giving oxygen is pumped around the pond system to where it is most needed. It is also the method of transporting waste products out of harms way. Just as with our own hearts, pond pumps should run 24/7 and any failure can quickly lead to catastrophic events. It pays then to pay particular attention to this essential piece of equipment. Above all else it needs to be reliable. Money spent on a quality water pump will save you time and help protect your fish.
A clogged pond pump reduces water flows dramatically and is annoying and time-consuming to sort out. Oxygen levels can quickly drop and waste products increase to dangerous levels. Although pond pumps should always be placed so that the water passes through the filter before entering the pump pond they should always be able to cope with a reasonable number of solids. Uneaten food, fish poo and plants, both dead and alive, can easily reduce flow rate.
Best Pond Pumps - Overall Winner
For all the reasons I have discussed below I have no hesitation in making the following pond pump my overall winner. This is the best pond pump currently available for the garden pond. It is a dedicated filter pump and does not come with any fountain heads. Although there are plenty of cheaper pumps available this range will pay for itself very quickly in reduced electricity costs, lower maintenance and greater reliability. In particular this pond pumps has;
- variable flow rate for summer and winter
- energy efficient with low power consumption
- soft start to protect motor
- run dry protection
- self monitoring fault reporting system
What kind of pump do I need for my pond?
A garden pond pump can carry out a number of different tasks. They can operate a fountain, numerous water features, waterfalls and, of course, a filtration system. This article primarily relates to pumps used to operate filters and waterfalls. Fountains and water features are usually for visual appeal and I shall be discussing these in a future article. Notwithstanding this some of the pond pumps listed here do come with a selection of fountain heads.
Within our main pond pump category there are a few different types,
i) Submersible Pond Pumps
All of the pond pumps listed here are capable of operating as a submersible pump. A submersible pump is, by far, the most popular choice for a garden pond. They can simply be dropped into the pond water wherever required and are free from any inlet pipework. Very often a coarse filter is built into the pump framework to keep our larger solids. Typically 4-6mm solids will be able to pass through the pump without problems. Naturally, submersible pond pumps are just as simple to remove, making them so much easier to free from blockage and other maintenance tasks. This is undoubtedly why they are so popular. One final point, If you ever intend to heat you pond then the heat generated by the pump is kept within the pond and not lost to the atmosphere.
2) External Pond Pumps
Some pond pumps can also operate as an external pump. This helps protect against water ingress but usually makes the dismantling of these a lot more tricky. Generally I wouldn’t advise perching an external pump garden scale operations.External Pumps are more useful for larger ponds. Koi keepers and commercial fish farmers prefer this type of pump. They tend to be more reliable and frequently, but not always, more energy efficient
3) Variable Flow Pond Pumps
These are amongst the very best pond pumps. The latest ‘eco’ versions from the major pump manufacturers incorporate variable flow rate. This is great to reduce electricity use and enables a slower pond exchange rate over the colder winter period.
What size pump do I need for my Pond
The first thing to say is that it is almost always the case that one pump should be all that is required. This needs to be situated at the lowest point in the system. Very often a sump tank will gather the water flows from all parts of the system and here is where the pump should be installed. From there it should be pumped to the highest point in the system. Again a dedicated header tank provides a lot of useful variations. From the header tank it should flow, by gravity, to each different part of your system. Valves on the gravitational side of the pump make for a convenient method of water distribution whilst maintaining maximum flow rate. The pond, filter, plant grow beds can all have their water flow rates independently controlled in the knowledge that everything ends up in the sump tank and doesn’t cause any balancing issues.
Having established that one pump is all that is required then determining the size of pond pump can often seem a little tricky. A number of factors will influence this including;
- stocking density – the more fish that are kept in a pond per unit volume the more water needs to be pumped into it to keep them adequately supplied with oxygen and to remove waste products such as solids and ammonia.
- feeding rate – this is obviously related to stocking density as well as water temperature and size and species of fish. Generally, the higher the feed rate the more water flow is required, for the same reasons as outlined in the previous point.
- plant stocking density – plants are capable of carrying out the same processes involved in a pond filter. However they tend to be less efficient and consequently far more plants are normally needed to achieve the same level of water purification. This may or may not be a problem depending upon you own objectives for your pond. It is perfectly possible to maintain a healthy pond without any pond pump, but the stocking density and feeding rate needs to be very low and the plant stocking density very high. This is the traditional approach for most garden wildlife ponds.
Bearing the above in mind the normal recommendation is to decide upon a suitable exchange rate for you own circumstances. By this I means how long does it take to pump all the water out of a pond. A 1000 litre pond with an inflow off 500 litres per hour has a 2 hour exchange rates as a guide the following exchange rates could be adopted. Equally a flow rate of 250 litres per hour is said to have a 4 hour exchange rate.
From the above a 2 hour exchange rate would be the best starting point for most traditional ponds and a one hour exchange rate would be best when growth is important. Aquaponics would generally fall into the later scenario.
Actual Pond Pump Flow Rates
Care is needed when it comes to selecting the best model out of a range of possible pond pumps. Manufacturers have the annoying habit of naming their models according to the absolute maximum water flow that each model is theoretically able to pump. This is at no head, no pipework and no frictional losses. Needless to say this is completely unrealistic. The head is the main deciding factor in calculating actual water flows. This is the height to which water is needed to be pumped. In our example above this is the difference in water level between the sump and the header tank. The greater the height the lower the water flow even though the motor is using just as much electricity.
Best Pond Pumps- Best Budget Buy
Firstly a small pond is really one with a volume of less than about 2000 litres. Based on the recommendation above of an exchange rate of 2 hours then these pumps will have a maximum pumping rate of 1000 litres per hour. These may be suitable for a water feature such as a fountain but they need to be suitable to operate a small pond filter. Consequently they need to have the following characteristics
- resist blocking. All manner of things can find their way into a pump inlet and reduce their performance. Uneaten food, leaves, snails, blanket weed, living and dead bacteria and fish can all cause problems. It is always sensible to protect the pump inlet with as large a filter as possible. Simple home-made gravel filters provide a cheap and effective solution in many cases
- easy to install, remove and dismantle. Even with careful design some debris will eventually find it’s way into the pump mechanism. The ability to quickly get at the impeller and give it a quick clean is an essential feature of any pond pump.
- energy efficient with low running costs. Garden water pumps need to operate 24/7. Needless to say even a small reduction inpond wattage can lead to significant savings over the course of a year.
Select the right model
You will notice that the major pump manufacturers produce a range of different sizes of a particular model. It is always a matter of balance between ensuring a good exchange rate and the cost of pumping. Generally speaking it is safer to err on the side of a slightly larger pump if unsure.
Alternative Pond Pumps for small ponds
Airlift pumps are based on injecting air into a tube to reduce its density such that the water pressure surround the tube will drive water up and through the tube. This sounds great and and can pump the maximum flow rate. The principle has been a very popular method of pumping water through an aquarium under gravel filter. The big draw back is that it can only pump water to a very low height. In essence it is great for general water circulation but not powerful enough to transfer water up into a filter. They are nevertheless, very simple and cheap to make and could prove useful for circulation and aeration within a pond filter. As a means of operating most pond filters they are not so great. There is still a reliance on a mechanical air pump and these tend to be less reliable than a water pump.
Solar Pond Pumps
Solar pumps are worth a quick mention. Their main drawback is obviously due to the fact that they do not operate 24/7. They are popular as they can simply be dropped into a pond without any wiring and can help to aerate the pond during very hot periods when oxygen levels may well be at their lowest. Their maximum flow rate however is tiny and should use one as an attractive water feature rather than something that adds much to water filtration.
- Select model based on actual expected water flow at 1.0 metre head rather than manufacturers claimed flow rate
- Ensure that the pump can be quickly removed and easily dismantled to clear any blockages when they occur.
- Protect inlet pipework with a simple gravel filter box
- Keep outlet pipework as large as possible. Small diameter pipe will always be a pain!
- Keep outlet pipework as short as possible, with the minimum number of bends and no valves.
- Check water flow regularly and clean impeller when necessary.
Most frequent questions and answers
Yes. Pond filters rely on living micro-organisms to purify the pond wastes. Without a flow of freshly oxygenated water these creatures will die and no longer be able to keep the pond water quality at an acceptable level. It is perfectly acceptable to turn the flow rate down in winter as less wastes are being produced but do keep some water flowing at all times.
Turning off the pond pump at night is absolutely the wrong thing to do. Oxygen levels will fall rapidly in the dark and endanger all pond life.
Again do not turn ff the pond pump in winter. It can be turned down, but not off. The bio filter is a living thing and, although running at lower capacity, will still need some oxygen to survive.
The answer to his question depends upon two main factors. the stocking density and the water temperature. In an intensive aquaculture situation all the fish can die within one hour if adequate backup systems are not in place. For most garden ponds the fish will normally be OK for a few hours if the water temperatures are not too high. Nevertheless they will also certainly be stressed and the provision of aeration by means of a pond air pump is highly recommended. Survival is one thing but stress does make future disease problems much more likely.
A good warranty period would be 3 years. The main danger is water getting not the electrics through faulty seals. Nowadays the electrics of small pumps are completely encased in a waterproof resin. The bearings and impeller are also doing a lot of work and can need replacement. These are usually available for the better makes of pond and are easy for anyone to replace.
Water pond pumps should be kept running 24/7 both summer and winter. The flow rate can be slower in the winter but it should not be turned off. The Blagdon…. is overall. one of the best pond pumps available today and consumes between 17 and 35 watts. If we assume the cost of electricity is £0.15 per KWHr then the annual running costs is between £22 – £44 per year.
The standard exchange rate for a garden pond is around 2 hours. This equates to a water flow rate requirement of 500 litres per minute. If the expected head loss is 1 metre the correct size pump in the Blagdon range is the model c
A waterfall will undoubtedly help to oxygen a pond. It is not a particularly efficient method of aeration but the more air and water is mixed the better he health f the pond life. It will also help to get rid of excess carbon dioxide produced by the fish, plants and filter.
It is highly unlikely that a tadpole will survive if it gets sucked up by a garden water pump. The trick is to not allow them to get into the suction. If the pump sucks water through a gravel bed before going to the filter everything should be fine.
Last update on 2021-10-21 / Affiliate links / Images from Amazon Product Advertising API