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About GaryD

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    Senior Member

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  • Biography
    I'm a micro-farmer....and the author of The Urban Aquaponics Manual
  • Interests
    Microponics, woodcraft

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  • Location
    Macleay Island, QLD
  1. Keep it up, Toga. I'm learning more about lighting with every post that you make. I would really like to build a grow room...with the ability to control every aspect of plant production...but the power (and heat) associated with HID and MH lights has been an issue...and I've found some of the claims around LED lights (not to mention the cost) a bit intimidating. What's your view of a hybrid set up...where the grow room functions as a greenhouse during the day and, at night, it gets closed up and the lights come on for a period? Feel free to take this discussion to its own topic if you want?
  2. What is your Malaysian aquaponics dream, VKN?
  3. Whoo Hoo! could be on your way to becoming a chicken wrangler, Brian
  4. The nitrification situation was never quite as simple (in terms of the bacterial composition) as we've presented it in aquaponics. There were always other organisms at play. For example, Dr Tim Hovanec determined (years ago) that nitrospira were the dominant species responsible for the conversion of nitrite to nitrate in freshwater systems....but the popular (non-scientific) consensus is that nitrobacter played that role. In any case, given that your system appears to be quite robust, I would be unconcerned about the possibility of toppling nitrification so long as the changes that you make are gradual and consistent. The role of plants certainly impacts the pH in any system but Mark McMurtry determined that, so long as he kept plants in the system, it became self-regulating around pH 6.4. He discoved that, if he removed the plants, the pH fell through the floor. In other systems, calcium (or other elements) is added to the system to offset the acidification that is occurring. This is obviously impacted by the fish biomass load (and the subsequent feeding rates) but I believe that any conventional aquaponics system will tend toward acidification over time. Of course, this will be offset by the use of media containing carbonates...or make up water with a higher pH. In my view, this is just as all aquaponics systems should be. The ability to isolate the fish from the plants is essential in the event of disease or infestation but it has other advantages, too...not the least of which is the ability to supplement nutrients from other sources. European researchers first looked at dual loop (decoupled) systems back in 2009 (I think) with a view to more effective nutrient utilisation. If I recall correctly, they concluded that decoupling was probably impractical for backyard systems.
  5. In my view, the best possible outcome would be for Trump to get ousted and to roll the dice again. Hopefully, the electorate would (having had the wits scared out of it) settle down to consider the benefits of social democracy....capitalism for the people if you wish. What the US (and the world) needs is a new economic and social order that is almost diametrically opposed to the one we have currently. It's time to care for people and the planet. And with that, it's time to go and fuel up the pigs and make sure the runway is clear.
  6. Dr Nick Savidov demonstrated that nitrifying bacteria survive below pH I wouldn't be too concerned about 6.5. This is another thing that you'll enjoy about iAVs if you decide to try it. The pH in an iAVs system regulates long as you have plants in the system. It seems that the soil microbiology that exists in iAVs knows a thing or two about such things. The key to pH adjustment is to make gradual changes.
  7. I find your use of Neem oil to be very interesting. Anecdotal evidence has always discriminated against its use around your use of it on your plants is an exciting development. The sand may limit the movement of the oil through the system in a way that doesn't happen with coarse media or raft systems. Either way, I'm watching it with real interest.
  8. Potatoes have been grown in iAVs...and VKN has grown something something called Chinese potatoes in his systems, too. They grow very well in wicking beds...which, in my view, are a logical companion for any aquaculture/aquaponics system.
  9. Hi Cecil, I'm hoping that the Trump dilemma resolves itself well before 2020. I have too many American friends to be comfortable with what he's doing to the US...and (as a resident of Planet Earth) I'm fearful of his impact on the rest of the world, too. Gary
  10. Hi Ian....leave the beans alone. Those aren't root knot nematodes....they're the nitrogen-fixing nodules that are found on legumes. Further to my oblique remarks about the plants in (other types of) media-based system...if this is what you can achieve in the face of root knot nematodes, the plant production is remarkable.
  11. Brian...try to get your pH down to sub-7.0....ideally at around 6.5...and you'll see some of the nutrient issues around your plants ease.
  12. Yes, I agree. It's great to see grow beds full of apparently healthy plants...a relatively rare thing in media-based aquaponics. It will be interesting to see the impact of the chrysanthemums and marigolds on the root knot nematodes. They may be a useful intercrop in areas where the nematodes are a problem. BTW....are the pink flamingos helping with the insect control?
  13. Yeah, I'm with you Cecil...I'm still trying to come to grips with it. The world is an increasingly queer place. Texas facilitates the keeping of backyard chickens and Trump pulls the US out of the Paris Climate Accord.
  14. As far as I am aware, most organic certifications of aquaponics systems relate to the plant growing aspect of the system....and not the fish. Certified organic fish food is still in the realms of the "nice to have" and can be difficult to find.