The Really Important Things You Need to Know About Your Pond Pump

Once the pond has been created and filled with water the question always is ... do I need a pump? The answer unless the purpose of the pond is to create a fairly large wildlife enviroment is yes. However the reason for needing a pump is not well understood.

The mere circulation of water around the pond using the power of a pump does little to enhance the wellbeing of pond inhabitants such as fish in particular. All that happens under these circumstances is that a degree of mixing of the pond water takes place. There is no great advantage in doing this.

The really important purpose of installing a pond pump is to supply life giving oxygen to a biofilter installed in the pond circuit. A second important reason and one which essentially complements the first is to use the pump to create a waterfall or cascading fountain since both of these allow lots of oxygen to be absorbed by the cascading pond water.

Fish, plants, and virtually all other living creatures including microscopic bacteria need oxygen to thrive. Consequently pond water with living creatures is naturally depleted of oxygen. In large masses of water such as rivers and lakes the depleted oxygen is replaced by oxygen entering the body of water at the air and surface interface. Wave action on lakes, riffles and waterfalls on rivers cause turbulence at the water/air interface and this significantly helps the process of oxygen transfer from the air to the water. In a garden pond this transfer of oxygen is limited by the surface area of the pond exposed to the air and the lack of wave action (turbulence). This is not to say that no oxygen transfer takes place but rather it is limited and this is especially so on warm still summer days. This very fact alone means that fish stocking densities must be very low to ensure the fish do not die from lack of oxygen. The fact is however that most ponds are overstocked and overfed which places an even greater burden on the limited oxygen concentrations in the water. It is not at all unusual for fish to die en masse under these circumstances.

This oxygen and fish stocking limitation can be overcome by using a pump to supply oxygenated water to a BIOFILTER and by returning the water coming out of the biofilter down a waterfall where the oxygen depleted water can be re-oxygenated. Inside the biofilter are millions and millions of bacteria that transform fish waste such as excreta and urine into non toxic chemicals. These bacteria need oxygen to complete this process of purification.

Since any small fish pond will almost certainly suffer from the lack of a biofilter it stands to reason that a pump is thus necessary in any fish pond, if for no other reason than to keep alive the bacteria inside the biofilter. It's important to note here that if the pump feeding the biofilter is stopped for anything more than 30 minutes or so then the bacteria inside the biofilter will start to die off (they deplete the remaining oxygen in the water standing inside the biofilter while the pump is stopped).

Once the decision to buy a pond pump has been made then it is important to specify the correct pump that will do the job you envisage. The 2 vitally important considerations to specify correctly are the water flow rate the pump must be able to handle and the head or height to which this same volume of water must be pumped. You can learn how to do this on the pump selection page.

On this same page you will be able to see how to specify the right pump if you have a waterfall in the circuit since this specification can be a bit tricky and most people get it wrong.

A further consideration when buying a pond pump is to consider the amount of power it consumes since this can be a very significant factor in the final choice of pump. In general the running costs of a pump are the more important aspect in choice as compared to the initial pricing. You will probably find find the page I created about the different pond and pump calculators useful if you are needing to buy a pump for the first time or need to get a new one. Then if you want to download the calculators free of charge go to Perfect Pond Keeping.

To see a wide variety of pumps with their basic specifications take a look at the pump review page.