Paul Dean

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About Paul Dean

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    Northen California, U.S.A
  1. Been thinking about this approach. Kellenw, what do you think is the best way to learn how to do this? I'll investigate the soil here, but I think it has a high clay content. The 'good clay seal'...does it require a layer of imported clay generally, or might it involve carefully compacting high clay content soil?
  2. There is a guy in Tennessee, USA, that grows algae in a pond (spirulina I think) by piping CO2 collected from distilling ethanol, through a perforated hose at the bottom of the fish pond. The CO2 bubbles through the water, and keeps the algae circulating (where it comes to the surface to catch the light before it cycles down deeper again). This stimulates accelerated algae growth, and algae is the sole feed for the fish. The fish are raised right in the pond along with the algae. He separates the fish from the algae with a screen for a couple of days before they are harvested, to rid them of the algae flavor. His system includes methane generation, ethanol production, and vegetable production. He uses captured heat from ethanol production to keep his fish warm. Mark Cardoso is the guy's name. He sells a manual telling folks how to grow algae (costs $180 US, so I have not seen it) but his approach is fascinating.
  3. Somebody in the San Francisco Bay Area is selling hot tubs (3-6 hundred gallons, and they have a couple of hundred tubs) for almost nothing. Would anyone care to offer an opinion about the suitability of those for raising fish? I am guessing that a smooth bottom tank would be better, but for 50 bucks each, a 400 gallon tank with a less than ideal shape might be worth considering. Some of these have a circular shape with a deeper "well" for human feet to rest in, and they also have a 'seat" molded into the design on one side. Will that make these fiberglass tubs difficult or impossible to clean? I intend on raisng Tilapia, at least to start, if the fish species matters in the calculation.
  4. If I get this, the implication is this cyclical die-off can be prevented by introducing several duckweed strains of different ages, or maybe periodically introducing new strains from different local sources?
  5. In the previous post I said "If I can get the fish-tank size and stocking density, to match the duckweed tank volume........" I meant......... if I can get the proper ratio of duckweed grow space, to fish tank size and stocking density, so that the proper amount of nutrients are filtered from the water by the duckweed........etc.
  6. Again, thanks for the feedback. So duckweed will remove nutrients from the fish-waste water at a higher level than grow beds (per equal volume and/or surface area), but will not re-oxygenate the water? What about a continuous feed, slow flow (entering at the bottom of the duckweed tanks) from crappie or bluegill tanks, into shallow duckweed tanks in a greenhouse, (where there is no wind, and something approaching ideal temperatures) then return the water through shower-head style bubblers into the fish tanks. If I can get the fish-tank size and stocking density, to match the duckweed tank volume, and if I "vacuum" solids off the duckweed tank bottoms, what additional measures might be needed to bring the water quality and oxygen levels back to where they should be for the fish? Also, does anyone see a fatal flaw in this concept that I might not have considered?
  7. Thanks folks for the responses. Gary, I have seen your article, didn't know it was you, but read it sometime back. Just looking to devise a system that works. Am considering making ethanol to heat a greenhouse, which means I will have CO2 to enhance plant growth. I am wondering if pumping CO2 on top of grow beds filled with water and duckweed, would increase the production? It seems like in a greenhouse, the CO2 would settle on the grow beds and stay there, possibly increasing yield dramatically. Any thoughts?
  8. I am wondering if anyone out there knows of specific ways to grow duckweed for maximum production. I've seen numerous references to duckweed in aquaponics circles, and clearly some folks are using it as a feed supplement for fish and animals. I'm not looking to debate the pros and cons of using it for fish feed, just interested in any info anyone has about how to grow it effectively, preferably in a greenhouse setting. I am thinking about the idea of a continuous flow system fed by a couple of tanks of some native N. American cold water fish. Seems like the challenge would be to keep duckweed from entering the fish tanks on recirculation, and to figure out how much duckweed growth and/or additional filtration, would cleanse the water enough for the fish. Or, could fertilize duckweed with compost, but stagnant tanks of water in a greenhouse sounds like a bad idea. I've seen it done in kid swimming pools, but does anybody really know how to do this effectively for sustained production/harvest?
  9. I think the concept of economic growth is definable in a range of ways. In assessing complex systems, like local national or international economies, metrics like GDP fail miserably to account for the factors upon which human life depends. I think an expanding economy counts for nothing if it is coupled with the contracting ability of the biosphere to support life, a rapidly expanding population, and depletion of carbon based fuel reserves. I think we need to engage our energies in an all out effort to grow food without petrochemical input, from feed to finish in a sustainable permaculture way. We should not keep adjusting food growing systems to conform to a doomed economic model, but instead work to develop ways to create local food self sufficiency in every region where it is possible, worldwide. Let economic systems adjust to the new reality...... of locally produced, sustainable food grown in small farms by large numbers of people. Heinberg can sound very pessimistic at times, but I think he is correct that we will have to live with less "stuff." For some that might seem dire, but I would trade an auto-commute- freeway- corporate- wasteland- world for more time spent at home producing good food. Heinberg talks about growth here, in the standard way economists think about it. I think it is obvious that model is doomed, and he is correct that GDP as measured by economists, will drop. We need a new way of thinking about economy and ecology.....one that may create some chance for us to survive.
  10. Thanks everyone for the feedback. So does anyone have a link or manual or book describing or showing plans for a DIY small/medium aquaponic system solids removal method? I've seen it described in outline, or for big systems like Jim Rakocy's UVI system, but still not clear where to go for direct info on actually building the things for the scale that I intend. Btw, the link for The Urban Farming Guys is very helpful. Their interests are definitely related directly to mine in this.
  11. Thanks for the link Ande. Been corresponding with Jim Rakocy about feed and other stuff, but this link is very helpful. Do most people use and consider essential, some kind of solids removal as a separate stage before grow beds? Rakocy makes it sound like it will enable a higher stocking density, but at what cost in setup and ongoing energy use? I was envisioning a flood and drain system without solids separation, but don't want to design a lame system. Maybe its just about how much fish I want to produce?
  12. Pugo, filter modules? A separate filter from the flood and drain beds? To remove solids? Was reading a little about this, but don't think I understand it yet. Is this the first place you pump water to out of the tank, then send it to grow/filtration beds? Is it needed for Tilapia production? I'm going to get some educational materials from the Speraneo farms, but haven't seen it yet. I don't think their system uses separate filter modules. As I said, I'm new to this, so just trying to understand the basics. Thanks both of you for feedback on IBC systems. It sounds like while they may not be perfectly ideal, there are no serious or fatal flaws associated with designs using them.
  13. Pugo, thanks for the tip about the Google tool. I have a "green" architect friend who is helping/partnering with my project, and I will rely on him for design drawings and greenhouse design. At this point I am not sure whether to design a system sized to create a desired output, and then size the greenhouse accordingly, or whether to design and build a greenhouse of a desired size and then install the most productive system I can place in it. My goal is to do research, and to grow enough to feed my family, plus enough to perhaps have a few "subscribers" for a bit of extra income. I am trying to get a handle on stocking densities, so I can have a better idea what yields will be. The early calculations I did based solely on internet research, seem to be based on overly optimistic numbers, at least according to an impression I am getting from poking around here. Question: What does anyone think of the IBC tote systems? Are those totes good for reliable tanks, and capable of producing efficiently, or are they simply comparatively cheap and available?
  14. I'm sorry, I don't know about the "google sketch up." Maybe I should?
  15. Hi folks, I'm new to aquaponics but absolutely fascinated by the possibilities. I'm Paul from Northern California USA. I'm dreaming up a small-medium scale solar greenhouse with aquaponics, where I will raise (most likely) Tilapia and vegetables in some sort of flood and drain beds. Am investigating the possibility of doing something like the Speraneo system in one temperature- controlled greenhouse,(using mostly passive solar heating and cooling) and having a cooler-water fish in a second much smaller greenhouse that is connected to a biogas generator. If we can do this, the biogas will be used to supplement heat during extended cloudy weather in the climate controlled Tilapia greenhouse. I want to grow duckweed as a large component of the fish food, and raise black soldier-fly larvae and possibly some seed crop, in an effort to create a closed loop (as much as is practical) feed and food production system. Would appreciate any feedback by persons knowledgeable in these endeavors, about the overall concept, what major obstacles I might encounter, etc. Looking forward to participating here, glad to know there are a lot of smart dedicated people working on these problems......thanks!