Normally a venturi is used directly in the main body of the pond, to provide oxygen and water movement for the benefit of the fish (some current to swim into). However I thought that a venturi dedicated solely to the bio-filter would provide it with additional oxygen, which "aerobic bacteria", vital for a bio-filter to work, require in order to live and work efficiently.
Some experts don't recommend venturis, as they can be inefficient devices because it forces the pump to push water through a restrictive venturi tube. Not only can the airflow produced usually be too small unless the device is placed right at the surface, but the final pump flow rate can be reduced by as much as 2/3rds! This means you would need a much bigger pump to power the system than required, just to power the venturi. This increases the initial cost of the pump, the running costs, and can reduce the life of the pump. This is true of "in-pond" venturis.
But venturis come in all types and sizes for different purposes. Industrial strength venturis, pumped using large electric motors for use in reservoirs, sewage farms, and water treatment plants, down to smaller scale for use in ponds. Venturis are also used to create the petrol/air mix in petrol engine carburettors.
When used directly in the pond, a venturi does require a considerable force to create good water movement, and a reasonably high pressure to "squeeze" the water and air together so making thousands of very fine tiny bubbles. Click for a more heavy-duty venturi design specifically for use directly in the pond.
Note: My venturi is intended to help oxygenate the bio-filter, not the pond.
You might consider having a seperate larger venturi fed from another pump dedicated to pond aeration itself, I do. To understand why it is a good idea, learn a little more about oxygenation at this link:
With the finished design, after flushing out my bio-filter as a part of routine cleaning maintenance, when I turn the pump back on again there is some slight spouting of water out of the air-intake pipe due to large bubbles being pumped through from the pre-filter, but as the air bleeds out of the system and it settles down the venturi effect starts to work and pulls the air in properly giving a constant sucking sound and air bubbles are properly fed down into the bio-filter. So when you start it for the very first time, expect it to act a bit like a "coffee perculator" until the air in the pre-filter and piping has bled through and out!
Put your ear next to the air-intake and you should hear a constant draw of air into the venturi, and of course should see the bubbles rising to the surface.
Nerf FIRESTRIKE Mod "Venturi Effect": 11 Steps (with …
This principle has been used since the 1960s in orifice plate traps, however industrial steam systems have varying loads, so the GEM trap was developed in 1995 with a “Venturi” to regulate condensate capacity under the full range of operating conditions.
Venturi effect explanation free
Many aquariums use power heads that include adjustable Venturi devices that consist of a tube that connects a water outlet with an adjustable air valve. The Venturi effect causes air to be pulled in through a short hose and mixed with the water that the aquarium’s pump uses in order to aerate the water. Carburetors, Venturi meters, water aspirators, cargo eductors, water evacuation from ship bilges, atomizers, foam firefighting nozzles, and protein skimmers are some of the Venturi effect’s commercial applications in society today.
Venturi Effect | Dynamics (Mechanics) | Hydraulic …
The Venturi effect was named after Italian physicist, Giovanni Battista Venturi, who lived from 1746-1822. Venturi was ordained as a priest in 1769 and was a student of Lazzaro Spallanzani. He is not only given credit for the effect’s discovery, but is also credited with the inventions of the Venturi pump and tube. He later compiled and published many of Gailileo’s manuscripts and letters after being brought to Leonardo Da Vinci’s attention.