What You Need to Know About a Submersible Pond Pump Before You Buy

There is such a vast number of pump models, manufacturers, countries of origin, brands and sizes that the correct choice is made very difficult. Often the final choice of pump is the result of a recommendation from a retailer and this might just not suit your needs. So take a few moments to absorb this page and you'll be a lot wiser.

Pump Facts that Apply to Almost All Submersible Pond and Garden Pumps

99% of pondkeepers will use a submersible pump. The need for a large out of pond swimming pool type pump is rarely necessary except in larger koi pond situations and these days submersible pumps have been developed that are suitable for these ponds too. So here we're concerned with submersible pumps only ...

Until a few years ago virtually all pumps for ponds came with a sponge on the suction side of the pump itself. This sponge was there to prevent pieces of debris (twigs, small stones and so on) getting caught up in the rotating impellor which more often than not would get damaged (the shaft would often break). The trouble with any sponge it that in summer, especially, it gets clogged up with slimy algae within days even hours and this means the output from the pump gradually reduces until it stops and you have to remove the sponge and clean it. Believe me this is a major messy hassle you don't need in your life. Pumps have now been developed and are sold by all the leading pump companies that do not need sponges. So lesson 1 ... never buy a pump that comes with a sponge
Pump guarantees ... the guarantee should never be less than 2 years and most good pumps come with a 3 years guarantee or warranty these days. The guarantee period is important not just to protect you against faulty workmanship it tells you that you can rely upon this pump to run in a pond environment. Conversely any guarantee of less than 2 years suggests that the manufacturer's confidence in that pump having a long life is not very high. If the supplier thinks this then you can fairly believe the pump is not suitable for a pond environment. Ponds are really rough on pumps.
Small fountain pumps designed to run in self contained re-circulating water features should never be bought for use in a pond. These pumps normally have short cables, are lightweight and come in small boxes. Make sure the box refers to pond pump.
Pond fountain pumps are available in a variety of stunning effects. It's best to get a separate pump for the fountain to make sure you always have the impressive effect. In other words don't share the flow with something else.
Information on the box can be misleading. This will be covered in more detail on this site but here are a few things to look out for ... Maximum flow is meaningless in a real pond situation, maximum head means that at that height the water flow coming out of the pump is zero. If Watts power consumption is not shown be wary since the pump then probably is energy intensive and remember a pump must run 24/7/365. Showing amps is not good enough. Look for flow rates at practical heights e.g. 3,000 litres per hour at 2 metres height (or head) ... this question of height or head is not as simple as it seems sop make sure if you want a waterfall pump you definitely read these waterfall and filter pump pages
Cable length ... in my country, South Africa, it is illegal to sell a pond pump for outdoor use unless it comes attached with 10 metres (33 ft) of specially formulated weather and waterproof cable. This is a prime safety requirement. This cable is expensive and for small pumps often costs more than the pump itself. Always go for a long cable if you use outdoors and do not cut it even if it is too long (this will invalidate any guarantee).
Believe it or not if you have a waterfall and also keep fish you will save a lot of money by buying 2 pumps ... we'll explain the 2 pumps story in detail later. This saving comes from using a small pump to run 24/7 to feed the filter which in turn means you can safely switch off the larger waterfall pump for most of the week.
Apart from dropping the pump and smashing it there are only 2 things that go wrong with submersible pond pumps. The impellor breaks or the motor burns out. These days both are rare. The motor is encased in resin for most pumps to ensure compete electrical waterproofing which means if a burn-out happens then the pump cannot be repaired and must be thrown away. If he impellor breaks then you need a new one. They are easily replaced without any tools in the case of most modern pumps.
Most pond pumps come from these countries ... UK, Germany, Italy, China and USA (almost for exclusive use in the USA. American pumps, in general, do not have the features and performance of other pumps. Until recently Chinese pumps were frowned upon but quality has improved dramatically. I always recommend a well known tried and tested brand pump for a pond because you want local attention and local support built into a branded product. Often I say a pond is for life and for your fish the pump is the difference between life and death. There is no room for pioneering in an attempt to possibly save a few pennies or cents.
Many good manufacturers do not sell under their own brand but allow other companies to brand for themselves ... good examples are Lotus who buy pumps from Project in Italy for example. I might be wrong but this was the case ... companies like Tetra, Interpet and others do not make pumps. True manufacturers (or companies that design and dictate manufacturing conditions) are Hozelock, Oase, FishMate, Heissner, Danner, Cal Pump. These are the pumps that I recommend every time.
Submersible pond pumps deliver different volumes of water depending upon these factors all of which will be discussed later ... length of pipe, diameter of pipe, height of waterfall, restrictions and fittings in pipe-work, restrictions to suction of the pump. You always strive to minimize the impact of these factors in choosing the right pond pump.
Units and measurements are bewildering to many people and it applies in pondkeeping too. Some talk of gallons, others litres, feet, metres, mm, cm and what have you. We'll try and make this problem area somewhat less painful for you. In general we'll talk litres, metres, and cm on this site.
Every pond would benefit form the use of an air pump but are not absolutely essential. Air pumps are essential in large koi ponds.
More and more pressurized pond filters are being sold these days for their significant advantages. These filters tend to need more powerful and appropriately designed pumps like those supplied by Oase Aquamax, Hozelock Titan, Heissner Aquacraft and Fishmate Filter Pumps are always suggested.
Try hard NOT to buy a solar pond pump if you want to use it in a fish pond without any other kind of pump that can run 24/7.

Always remember this ... if you switch the pump off overnight the bacteria die and this means the water purification process being driven by the bacteria inside the filter comes to a grinding halt. In many such circumstances fish become extremely stressed and may eventually die. You can learn all about these pond filter bacteria here.