Two types of MTFs are described in the new Danish legislation (Danish Ministry of Environment,Ģ012), referring to farm size prior to regulation by emission concentrations. I think the Danish MTF (Model Trout Farming) are "state of the art" within airlift driven ras (95% recycle of the water with ground water as makeup) at the current timeĬut/paste from page 9/10 in this doc./pdfįeeding in MTFs is typically carried out using demand feeders or feeding continuously duringĭaylight hours using various automatic feeding systems. To me the question should be more about what's the max water movement (turn over or air) the fish could handle rather than min turn over. More O2 = more growth so no point in shooting for the min turn over. Since you're going for max growth I don't think you'd want to cut any corners. Combine that will aquaponic data and you should get a reasonable idea when filters are used. For enclosed systems I think you'd want to look at people keeping trout in mud ponds to see what kind density they get before troubles. All the trout rendering ponds I've seen have been flow thru systems, no filtering. If we're talking about trout the water temp would be a factor because bio filtering bacteria have a reduced conversion rate as temps drop. When you design those systems you normally find yourself in a reasonable turn over. For example a BD will require a min flow, a skimmer requires a certain flow, a moving bed requires min flow, showers, etc. Meaning you probably wouldn't want to go much below the flow rates they're using for high density. But really all the commercial aquaponic systems I've seen or read about the filtering was pretty basic. While none were low density it did leave me with an impression of how much each parameter changed and from there I could make a guess. I've read some data from commercial aquaponic people where they've varied the fish load and they talk about what happened at different loads. There is very little aquaculture data on low density fish culture.Good point. So anyway this is why I asked about rules of thumb. Same species with no astaxithin added to the diet: I even add astaxathin to the diet to bring out colors probably similar to what you folks with your koi diets. lower, it will actually be a partial recirculating system due to the fact that salmonids don't tolerate nitrates as well as other species ,and I need to keep it cool with the use of a small amount of continuous ground water, and viewing the fish is not paramount but does coincide with low suspended solids. With my trout niche market that need to have perfect fins and no blemishes, and my trout are sold at very high prices it's pretty much exactly the same thing you folks are doing with the only difference being my temps will be about 20 degrees F. This is why I like to pick brains on the koi site from time to time. There is very little aquaculture data on low density fish culture as it typically doesn't make money and they sacrifice aesthetics for profitability. However my fish will be low density high value fish where water clarity and low suspended solids are just as desirable as koi, only my fish will be trout. Good comments and I understand what you are saying about aquaculture data etc. But it's better imo to make an educated guess based on the actual pond design, owner's goals and real data rather than the most commonly typed number on the web. And even if you plan on having 10 Koi in 500 gal and go by those dozen opinions it can turn out poorly if it turns out all those people were in cold climates and your water temps are much higher. Or a dozen people with 10 large Koi in a 500 gal pond who say the minimum turn over rate is 20 minutes. You can get a dozen opinions from people with 3 goldfish in a 1000 gal pond who say whatever turn over they happen to have is perfect. For picking one of those it comes down to just a guess. The internet rules of thumbs I consider to be more misleading than helpful. All of these would have their own scientific flow ranges for different fish loads, feeding amounts and goals. Moving bed filters require way less flow than static submerged media. Flow thru water can be used instead of bio filters. Air diffusers can be used instead of pumps. Lots of testing and have plans for adding more as needed. To me if the plan if for high fish loads the source of info should be based on data gathered scientifically which means fish farming type data. And no toilet, well you don't want to be feeding 100 people a lot. 100 people in the room means people could start passing out. I can live comfortably in a an fairly enclosed 12x12 room with no ventilation. I relate it to something I can understand, people in a room. But if you look at the reasons for increasing or decreasing turn over you move from the world of opinion to science. There are rules of thumb for turn over.everyone has one.
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