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Shelf Aquaponics

Discussion in 'Aquaponics Ideas' started by pkoay, Jan 13, 2016.

  1. pkoay

    pkoay New Member

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    Hi all,

    I'm very new to aquaponics, only read a few things so I'm keen for some feedback. I want to build single shelf system for suburban hobbyist that requires minimal space (e.g. for a unit balcony) that has a high density fish stocking. Below is a basic diagram of what I have come up with:
    upload_2016-1-13_10-8-50.png

    This is different from the standard Chift Pist System:

    [​IMG]


    The main differences is the water flow, in my system :
      1. Water pumped from sump on to the grow beds (not into the fish tank)
      2. Water flow from the fish tank goes to the sump (not grow beds)
      3. Water from grow beds goes into fish tank (not sump)
    The reason I think this might be a good idea is that Solids Lift Overflow will put the waste in the sump tank swirl filter, not back up in the grow media (i.e. less cleaning)

    However as I have no idea why the water flow is set up in the Chift Pist, maybe I'm missing a critical point.
    Any comments would be greatly appreciated!

    Cheers,
     
  2. yoodles

    yoodles VIP Supporter

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    high fish density means you have to have lots of grow beds -
    high density meaning lots of fish for a small L of water - or - lots of fish minimal grow bed space?
    ie. are you trying to put 20 fish in a 300L tank with say 3 growbeds or 50 fish and running only a single growbed?

    weight is the key issue - water is heavy.. lol balcony's would only have a rating of between 500 - 1000kg's per sqm.
     
  3. yoodles

    yoodles VIP Supporter

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    if you want light and simple then use NFT rather then growbeds, you will need to run from the fish tank into a RFF and then into an MBBF with something like K1 media in place, pump up to the nft lines and then back to the fish tank.
     
  4. pkoay

    pkoay New Member

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    Hi Yoodles,

    Thanks for you input. The main reason for the 'blurb' at the start was to give the shelf system some context. I see now I shouldn't have done that rather just said it was a shelf system with the main fish tank being a 4'. I am mainly interested in some of the background knowledge on why the Chift Pist System flow is that way and why something like the system I the proposal is not a good idea.

    On your posts tho:
    Great points about the weight on the balcony and on NFT being lighter than media beds . Definitely something I should keep in mind.
    Also good points that I could replace swirl filter with RFF or even a clarifier.
    When I say high density, I meant lots of fish per litre of water. Was thinking to maybe use a aquarium filter if I don't get enough filtration from the grow beds.

    Thanks!
     
  5. yoodles

    yoodles VIP Supporter

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    you will still need to get rid of excess nitrates (this is what you do with a water change in an aquarium)
    this is also the reason you dont need to do much in the way of water changes with a well planted aquarium and low fish load (ie. my main aquarium rarely gets water changes)
     
  6. davidl

    davidl Member

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    All good points from yoodles. You need
    • enough aeration per fish
    • enough surface area of growbed or filter media per gram of fish food per day for bacteria to grow on to convert ammonia to nitrate. Since aquarium sponges and the plastic K1 media are much lighter per surface area that would be good to replace much of the classic grow beds with filters and NFTs.
    • enough plants per gram of fish food per day to consume the nitrate or do water changes like for an aquarium. One square meter of high density plantings will consume enough nitrates from the fish food required for up to 15 fish. People working on the 1 fish to 10L tank to 10L grow bed (30cm deep) guideline are essentially doing 30 fish per square meter of plants, and will often end up at the upper limit of number of fish they can have. This results in them having to clean out lots of gunk out of their system and sometimes even requiring water changes. A huge waste. Yabbies4me on this forum often goes on about how few fish are actually needed to feed plants, I agree. I've had some grow beds pulled out of my 1st main system for over 2 years, and have just been using them as pot plants, and they still have enough food in them to grow pineapples. Fewer fish = fewer problems. For my next main setup I think I'll try 5 fish per square meter of plants.
    • a small enough number of fish to be happy with the lesser amount of those fish food per day figures.
    • enough water in the fish tank to cover the fish so they aren't stressed at the water level. This is a surprisingly small amount per fish. I've had 50 fish in a 500L tank and it looked like they would have been equally happy with 250L. Though whenever I removed the lid on the tank mayhem ensued as they all tried to reach the bottom and squeeze into the shady part. They probably squeezed into a volume of about 50~100L. Though if I had drained the tank down to that level permanently they would have been overly stressed.

    The term chift pist is a little vague as to where in the system the grow beds are. That being said, a common setup has the water flow fish tank -> grow beds -> sump. Having the water flow from fish tank to grow beds then to the sump reduces the amount of solids going through the pump, and this reduces the issue of the pump chopping up the solids into very fine solids that fish don't like breathing, no more than you like breathing dust. Some fish are more susceptible than others for the amount of fines in the water. Also when you have worms in your grow beds, as most backyard systems will naturally develop, they will liquefy any fish solids into plant food, so having the solids go into the grow beds is not a big deal in a backyard system. For a backyard system this means they don't need to clean sponges or other filters, and if they have enough grow bed media per fish then they practically never need to clean the grow beds either. I've heard people that have been running grow beds continuously for more than 5 years without it clogging up or developing dead spots.

    All that being said
    • a sump may actually be a problem for balcony systems, due to the increased weight of having a sump. As yoodles pointed out, water is heavy, and simply having a sump increases the amount of water you have.
    • In addition to the light filter media and NFT, I would have at least 1 small grow bed with the expanded clay (hydroton) pebbles for worms to live in. The expanded clay is lighter than gravel. I'd also try and figure out a way to plumb the system to test having the filter/NFT part before or in parallel with the grow bed.
    I'd try having the filter/NFT in parallel with the grow bed initially to give you
    • pump in fish tank flows to both
      • small grow bed -> back to the fish tank
      • and light weight filter -> NFT grow channels -> back to the fish tank.
    This eliminates much of the weight, the worms have a safe place to live, and you can squeeze the filter sponge into the grow bed if you think the worms can handle it, or into some pot plants if you think the grow bed has enough gunk in it already. If it turns out that your worms can handle the amount of fish solids then you can change the plumbing to go fish tank -> grow bed -> filter -> NFT to reduce the frequency that the filter needs cleaning. Note that while moving bed filters usually don't need cleaning they will not provide mechanical filtration and all of the solids will end up in the small grow bed anyway. Simple cheap filter sponges provide both mechanical and biological filtration, and a simple squeeze out will be enough cleaning. Buy the stuff with the large holes because the fine hole sponges clog up far too quickly.
     
    Last edited: Jan 31, 2016

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