Re: BYO Farm Pond Aerator
Hi, a couple of points for you to consider.
Very little airation occurs when the bubbles are floating to the surface, believe it or not. The bulk of the airation occurs when the surface tension of the water is broken by the air bubbles. That is when oxygen is taken into the water and circulated.
The most efficient "container" for fish is the one that presents the most surface to the atmosphere. The temperature of the water also determines how much oxygen can be stored in the water, the cooler the better.
A cheap but very efficient way to airate water is to build a "rock slide". This is where you circulate the water to a higher point, say 3 - 5 foot above the existing water level. Between this higher point and the pond is a long "slide" sat 30' or so, made of concrete and embedded with a whole bunch of rough rocks that serve to break the water flow to create lots of agitiation in the water. This will in turn break the surface tension of the water allowing it to gather oxygen on it's way back down to the pond. In so doing you are recreating mother natures flow of fresh oxygenated water from a from a river into a pond.
Depending on the pond size you can build a very efficient bilogical filter in line with, and just before this rock slide. It will be powered by the same pump.
You also have to be very careful of messing with the thermoclines (the various water temperature layers) in the pond.
Plants (weeds) are wonderful oxygenators, get the right plant, one that is easy to grow and one that is an efficient oxygenator. Secondly the roots of the plants absorb the mulch on the bottom which they use as food. It is a question of balance.
Plants are also great spawning places as wekll as hiding places for newly hatched fry.
Photosynthesis relies on carbon dioxide, released by the fish, which the plant then converts into oxygen. Oxygentaing the bottom layer will not have the result you desire, let the plants do their job.
It may be that you are overstocked (if you are farming fish) and you are perhaps overstressing the pond. Do some googling, there are formula's available that allow you to calculate the surface area required per inch of fish, some of these quote the water temperature as well as if you have additional artificial airation.
All my tropical tanks never had airators. I calculated the amount of fish that could be held for the given temperature of the water and surface area, planted tons of plants and always had a three stage biological filter. I did however have a under gravel heater which accelerated the breakdown of the mulch.
Another odd fact is the larger the eco system the easier it is to maintain once balance is achieved.
My thoughts.
Cheers
Andrew