The basic techniques for aeration of ponds and lakes are the following:
Waterfall, Venturi Tee, Degassing Towers,and an Air Lift .
The waterfall can be an aesthetic form of aeration if it is very turbulent in design.
The water must be spread out over rocks into a thin sheet so the bad gases can be expelled and oxygen gained.
The more splash the better. A longer waterfall with many splash points will give greater benefits than a short one with few splash points. A stream bed incorporated into a waterfall will give a longer contact time with the atmosphere. A waterfall which simply sheets over one drop before hitting the pond surface does little for aeration. A waterfall as the main source of aeration is expensive to run electrically.
A typical pond water pump can cost you 300 to 500 watts. In comparison an air lift powered by a HAKKO air pump can be as little as 40 watts. Waterfalls can be loud at night and some people turn off the waterfall before bed so as not to disturb the neighbors. This is always a bad idea and a detriment to the fish and pond unless supplemented with a HAKKO air pump which are very quiet.
Venturi Tees can be added to the outlet pipes of your water pump as a jet retuning to the pond. They are positioned near the surface and as water is pumped through the tee air is drawn into the flow of water and pumped out into the pond.
This creates surface turbulence. These can add oxygen if the pump is powerful enough. For the venturi tee to work properly a lot of water must be forced through it. This puts a lot of back pressure on your water pump.
You may be gaining aeration but you will lose water flow. This can be to the detriment of your filter system flow if on the same circuit.
The trade off is a higher electric bill to power a bigger pump. For the electrical cost versus aeration gained, the venturi tee cannot compete with the HAKKO air lift.
Degassing towers otherwise known as trickle towers, can be used to aerate water or de-gas unwanted gases from the water. Water is pumped up to a column or tower and sprayed down over plastic or natural material called “packing” which breaks up the water many times as it splashes down through the material.
This vigorously aerates the water and allows bad gases to be released. To be effective this device needs to be quite tall and obtrusive.
There is also considerable electric cost to pump the water to sufficient height. If the obtrusiveness and electrical costs are inconsequential, a trickle tower can be an effective aerator.
They do offer the added benefit of providing additional biofiltration due to the biofilm of bacteria which will grow on the packing material surface area. For the average pond hobbyist or lake manager, a degassing tower is not a practical way to aerate. They can be complicated and require considerable engineering compared to the simple efficiency of a HAKKO air pump with an airlift.
HAKKO air pumps give you the ability to aerate and circulate your pond or lake at great efficiency. The amount of power it takes to inject air bubbles to the bottom of the pond is very small compared to the use of a water pump.
In fact, HAKKO air pumps out perform the competition in longevity and output. One look at the performance curves will reveal that HAKKO actually produces more air than advertised! The 40L actually delivers almost 60 liters per minute at 1 meter depth!
The 80L delivers 100 liters per minute at 1 meter! You get a bigger air pump for the value. All pumps have a peak performance at a depth of approximately 2 meters.
This means you get the rated volume of air for that pump with the best energy efficiency. Example: a Hakko 80L will give 80 liters per minute at 2 meters deep and pull approximately 80 watts of power.