How to Add Oxygen to a Garden Fish Pond Using an Air Pump and
Waste builds up on a pond bottom. Oxygen is needed to break down this waste.
Fish need oxygen just to survive. At night plants need to absorb oxygen from
pond water. Most important of all the massive quantities of nitrosomonas and
nitrobacter bacteria in every pond filter system need large quantities of oxygen
to enable them to survive and remove pollutants from pond water. A great deal of
the debris you see on the bottom of your pond starts life as a windborne bit of
debris that for a while floats on the pond surface. If the debris is allowed to
sink it becomes unsightly and if organic in nature it also consumes
precious oxygen in a pond to be able to break
down the organic waste.
In summer and on calm hot balmy days ponds with lots of fish may suffer from
oxygen deficiency. The fish and other parts of the oxygen consuming systems are
thus threatened by a lowering of levels of oxygen and when this is coupled to
the fact that warm water can hold less oxygen than cold water the threat of fish
stress and even death can become real.
Air contains about 20% oxygen with the rest being mainly nitrogen, carbon
dioxide and small quantities of minor gases.
At higher altitudes water can hold even less oxygen than at sea level.
Why It's Easier To Keep Goldfish or Koi and More Difficult To Keep Trout In
Trout are fast moving predators and thus need lots of oxygen to keep their
metabolism working. For this reason they prefer colder water (because cooler
water holds more oxygen) fast moving rivers and streams in which the maximum
amounts of oxygen can get transferred in the turbulent waters.
Koi and goldfish are members of the carp family and this type of fish prefer
warmer (less oxygen dissolved in warmer waters) water. They are also grazers or
bottom feeders and don't need the speed to catch food.
Avoid Fish Stress in Overcrowded Garden Ponds ... Use An Air Pump
An air pump is situated outside the pond. The air pump is then connected
using small bore plastic tubing to a series of air stones (porous ceramic blocks
in round or rectangular shape). The air pumped into these air stone becomes very
diffused into tiny bubbles that rise to the surface of the pond ... as these air
bubbles rise in contact with water some of the oxygen inside the bubble finds
its way into the pond water and this process repeats itself continuously. As
such the oxygen that is taken up by fish, plants, bacteria etc is replenished
and all pond inhabitants remain happy and unstressed.
The Different Types of Air Pumps
The first thing to take into account is that high quality large koi pond air
pumps are expensive because they need to deliver lots of air to significant pond
depths. Most large koi ponds are at least 6 feet deep and adding air to water
through porous air stones at this depth takes a lot of pushing. Air pumps are
specified based on maximum depth to which they can pump and the volume they can
deliver normally expressed as litres per hour (lph) or cubic metres per hour.
Larger sized air pumps can also deliver through multi ports to differently
located air stones.
Most air pumps need protection from the rain and severe weather so are bets
kept in protected areas.
Bradshaws supply air pump models from Oase, Blagdon and Gardena. It's a case
here of you get what you pay for so if your serious about fish keeping and you
believe you'll benefit from adding air (and every pond will) then go for the
best you can afford.
I would recommend the Blagdon Koi Air pump products. These come in 3 model
Koi Air 25 ... air output is 1500 lph at a
maximum depth of 2.2 metres and can supply up to 6 air stones
Koi Air 50 ... air output is 3000 lph at a
maximum depth of 3.0 metres and can supply up to 12 air stones
Koi Air 65 ... air output is 3900 lph at a
maximum depth of 3.5 metres and can supply up to 14 air stones
The Smart Solar Oxygenator is an ingenious air pump suitable
for small to medium sized ponds, complete with 2 air stones. Working
via solar power this air pump oxygenates pond water in sunny weather
when oxygen levels are depleted. Powered and supplied with a separate
solar panel. Simple to install, there are no wiring and no running