Pond Boss Forums INTRO Questions & Observations Georgia Giant Put to the Test?

I do not consider myself a expert in every part of the auqaculture area but I do know some basic concepts.

The methods that you promote to grow the GG's push the limits for reliably and consistantly growing healthy fish. When at or above natural carrying capacities things can turn "bad" very quickly and some water quality parameters can kill fish very fast. Many times when dealing with all this "fish stuff", it always depends on the variables. This is why there can be so many ways to "get it done" and often it works. Sometimes it fails.

Deb asks I am not sure what you mean by pulling the deeper sediment? Sediment as in pond bottom sediments? Or do you mean deeper water near the sediment (6ft-8ft)?

I will assume you mean will the high volume of water moved in such a small pond cause the whole water column to be mixed. Again, it all depends. It primarily depends on degree of thermal stratification (resistance to mixing) and the amount of wind action which will usually be comparatively small in only a 1/10 ac pond. Very little wave acion will be produced even in a strong wind. Even though one is mechanically moving lots of water, the downward mixing force of the lateral surface currents is quickly dissipated as the lateral currents move outward and down toward the cooler pond bottom. The downward moving water will seek the path of least resistance as in travels down toward the cool water zone on the pond bottom. Whenever the downward moving water looses more energy than it has to push against the cool layer, the down moving water will then travel laterally back toward the strongest water movement source (aerator intake). The laterally moving water travels on top of the cooler water layer beneath it. Water pushing against water quickly (compared to air movement) looses momentum because of the fluid mechanics of water.

This whole concept is why bottom diffused aerators are better at mixing the entire water column (the driving and uplifting force of water entrained in rising bubbles begins at the bottom and usu deepest coldest part of the pond) compared to surface aerators that are sucking water from the well mixed and easily mixable upper, warmer, water layer. But keep in mind that surface aerators are better than bottom aerators at creating a highly oxygenated zone in the vicinity of the aerator. Often, just a high amount of DO in a small area will be enough to get most fish through a short, mildly stressful condition. And providing the fish are smart enough to recognize that the noisy, oxygenated refuge area as beneficial.

Deb asks - Both units have benefits. If I had to choose only one, I my opinion, surface aerators are best for shallow ponds such as hatchery ponds (3'-6')and bottom aerators are better in deeper ponds (7'-20'). (See NOTE below). But again, it all depends and there will be exceptions in many cases. I can quickly think of several. If I stocked at the rates Ken et al recommends I would have both types of aeration or at least have a surface aerator available when deteriorating water quality conditions occur.

NOTE: Ken et al probably hear success stories with surface aerators in deeper ponds and this is why he promotes them for all ponds shallow and deep. He has seen in many situations or instances the surface aerator can provide marginal and survivable conditions for at least some or most of the fish when things "turn bad" (thermal turnover) in a deeper pond. Bottom aerators tend to minimize the frequency of "things turning bad". There are trade-0ffs.

Survivability of fish in deep water ponds with a surface aerator, during a thermal turnover or during other poor water quality condition or COMBINATION of conditions will be dependant on numerous factors. I will not elaborate on them here. Many factors, biological and chemical, can interact to determine if fish live or die during a stressful period.

Deb asks - In my opinion no. The ammonia is a much tighter bond to the water molecule and the affects of the propeller is so gross in comparison, the propeller design should have no measurable impact to separate the ammonin from the water molecule. Keep in mind that the ammonia is not dissolved in the water but chemically bound to it. The aquaculture industry and sewage treatment industry have special strippers and extractors that are specially designed to remove gasses and dissolved organic solids such as proteins from water. However somtimes to strip certain chemicals from the water (break chemical bonds) the chemistry of the water has to be modified.

Your post above mentions that "you" (the hatchery) monitor various water perameters on a regular basis. Also in this regard, Ken et.al. has quite a bit of experience in knowing what "signs" to look for and WHEN problems are likely to occur. Often it is very subtile clues are signs of upcoming major problems. I think the majority of Ken's customers (novices), who follow his stocking advice closely, do not have his expertise, experience or capabilities and thus they probably obtain less than optimum results. The general or typical customers have a very wide range of background knowledge, fish raising experience and pond management experience. The various pond conditions throughout the eastern US are also widely variable. You probably do not hear a lot about great results from many of these growers. I think the truly successful customers are mostly the lucky ones, and "things" did not get "complicated" for them in their fish raising project.