| Pond Aeration - Garden Ponds & Larger Ponds |
POND AERATION
Dissolved
oxygen analysis measures the amount of gaseous oxygen (O2)
dissolved in an aqueous solution. Oxygen gets into water by
diffusion from the surrounding air, by aeration (rapid movement),
and as a waste product of photosynthesis.
Environmental
Impact:
Adequate
dissolved oxygen is necessary for good water quality. Oxygen is a
necessary element to all forms of life. Natural stream purification
processes require adequate oxygen levels in order to provide for
aerobic life forms. As dissolved oxygen levels in water drop below
5.0 mg/l, aquatic life is put under stress. The lower the
concentration, the greater the stress. Oxygen levels that remain
below 1-2 mg/l for a few hours can result in large fish
kills.
Dissolved
oxygen concentrations may change dramatically with lake depth.
Oxygen production occurs in the top portion of a lake, where
sunlight drives the engines of photosynthesis. Oxygen consumption
is greatest near the bottom of a lake, where sunken organic matter
accumulates and decomposes. In deeper, stratified, lakes, this
difference may be dramatic - plenty of oxygen near the top but
practically none near the bottom. If the lake is shallow and easily
mixed by wind, the DO concentration may be fairly consistent
throughout the water column as long as it is windy. When calm, a
pronounced decline with depth may be observed.
Seasonal
changes also affect dissolved oxygen concentrations. Warmer
temperatures during summer speed up the rates of photosynthesis and
decomposition. When all the plants die at the end of the growing
season, their decomposition results in heavy oxygen consumption.
Other seasonal events, such as changes in lake water levels, volume
of inflows and outflows, and presence of ice cover, also cause
natural variation in DO concentrations.
A proper pond aerator is vital to having a
healthy koi pond, water garden or lake no matter what time of
year it is. Use a pond air pump during hot weather to
provide the necessary oxygen. During the winter an air pump
will keep an opening in the ice, add oxygen and help gas off
toxins.
Any system
will benefit from adding an aerator. An air pump will
also help the growth rate of your fish, both koi and
goldfish. Adding an aerator will also help the biological
process within your pond. Biological filtration
requires large amounts of oxygen so pond air pumps
should be used.
Oxygen in
ponds comes from two sources--photosynthesis and diffusion from the
air. The most important source, photosynthesis, is the process
plants use for manufacturing food. In the presence of sunlight,
plants (especially algae) add oxygen to water as a by-product of
photosynthesis. At night, no oxygen is produced, but respiration of
algae, fish and bacteria continues to remove oxygen from the water.
Most of the time there is a desirable balance between how much
oxygen is produced and how much is used, but under some conditions,
the balance can be upset, and the oxygen concentration becomes low
enough to stress or kill fish. The amount of oxygen in pond water
can vary considerably from pond to pond and from hour to hour.
Typically, however, oxygen concentrations are lowest at dawn and
highest during late afternoon.
The amount of oxygen water can hold is dependent upon atmospheric
pressure, salinity and temperature. Water can hold less oxygen as
altitude increases. Salinity is not important for most freshwater
fish producers. The most important factor is water temperature. As
temperature increases, water can hold less oxygen. Most low oxygen
problems occur from June through September. The reasons for this
are:
- Water can
hold less oxygen as it becomes warmer.
- Respiration
rates of both plants and fish increase with the warmer water, so
more oxygen is used.
- Summer's
still, hazy or cloudy days may reduce the amount of oxygen
produced.
- Large amounts
of feed given to fish at this time of year result in large
quantities of fish waste which create a higher demand for
oxygen.
TJB-INC offers several different styles of Areation
Systems. Both for large ponds or lakes, and for smaller water
gardens like the kind we would enjoy in our own backyard.
