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DIY Swirl Filter for aquaponics "davoponics"

Discussion in 'Filters - How to build - What type -' started by doctorjuit, Jul 13, 2011.

  1. doctorjuit

    doctorjuit New Member

    Jun 17, 2011
    A swirl filter or solids filter is occasionally used in aquaponics to remove particles of fine fish waste. Suspended matter in the form of fish poop, floating debris, food particles are removed to clarify the water that flows back to the fish tank. Improved clarity of water aids fish health.

    It also stops clogging the plant roots in a floating raft (DWC) aquaponics system and aids in the ability of the plants to absorb oxygen and dissolved nutrients.

    In a conventional aquaponics system, your growbeds are in a way – your swirl filter. So extra filtration usually isn’t required. Most growbeds do a very good job in reducing the amount of impurities in the water that eventually cycle back in a recirculated aquaculture system.

    Compost worms in the grow bed further help mineralise that fish waste and reduce the load that a basic system can handle.


    But sometimes – depending on fish stocking densities and on what species of fish is used in an aquaponics system – a swirl filter is a good idea to reduce the amount of solids in circulation.
    If you find your water getting cloudy on a regular basis and the fish hard to see in a hazy murk – then maybe adding an extra growbed – or an additional solids filter might be the way to go.

    DIY Swirl Filter

    There are many commercial models in production that can cost hundreds of dollars. For those on a budget making your own swirl filter from a plastic drum and a cheap plastic laundry basket might be a better alternative and save you a ton of cash! A Do-It-Yourself Swirl Filter may not look very flash – but if it does the job keeping your fish water clean – then who cares!

    One person who has studied swirl filters and how to use them effectively is Australian school teacher and Aquaponics enthusiast Dave or “Daveoponics†as he likes to refer to himself on forums.

    Dave raises Barramundi and Tilapia in Brunei in a tropical climate.

    Barramundi or Sea Bass fingerlings as they are known over there are a lot cheaper to buy than in Australia and a natural way to secure clean organic fish for Dave to feed his family as well as growing the kinds of vegetables that are not easily found in the local Asian market.

    If you read my recent post on barramundi you would know that these fish are notorious for pooping a great deal and when you overstock your system with too many fish – you need to find a solution to keep the water sparkling clean.

    Building your Own Swirl Filter

    Dave built his own swirl filter from a 200 litre blue barrel and a plastic laundry basket. Notice the construction of his spray pipes and the elbows that can be adjusted to direct the water flow in a centrifugal force or “swirl†pattern.

    Solids are swirled to the sides and deposited at the base of the blue barrel before the cleaner water makes its way to the grow bed eliminating the heavier solids.

    The laundry basket made a neat fit into his DIY blue barrel. He then found a sheet of thick foam and lined it around the inner wall of the laundry basket. At the base of his basket he used some natural coral for additional filtration,

    His system works very well and traps all the fish waste that his 100 barramundi produce. Cleaning the Swirl Filter is pretty simple. He can drain off the sludge by adding a small tap at the base of his barrel. The whole thing can be easily hosed out with a pressure hose as well.

    Dave explains how his system works, “I made the drain dead centre in the bottom of the barrel. It is a bit more effective in removing all the muck but not critical.
    I divert the waste pipe into my Papaya patch and everything in the dirt there is thriving. It feeds Paw paws, passionfruit, parsley, okra and indirectly the squirrrels who seem to think I’m growing all this stuff for their family.†he said.

    “I drilled the bottom of basket with holes, lined edges with aquarium foam, in the middle is a laundry bad full of coral. You could go to town and fill the whole basket with light medium I suppose, but I have found the foam and coral work well. On the other filter I have filled the basket with some of those aquarium filter “toilet brushesâ€. It works even better. The whole unit is really easy to clean. I just hose it out every few weeks.†he said.
    “It is easy to make.†he says, “I’m sure there are better filters (out there) but as a DIY one this is simple and works.â€

    Dave has two swirl filters on his other systems. Both filters sit about 1 metre off the ground on heavy duty hardwood stands. The water is pumped from the center of the Fish Tank and gravity feeds down to the top of the barrel swirl filters and then on to the Grow Beds.

    “The one improvement I would suggest to the design is to put a conical base in the drums to help drain the solids.†said Dave, “When I clean the filters I just hose them out so they are low maintenance.â€

    Commercial Swirl Filters are further discussed and demonstrated in the Aquaponics Secrets DVD that we produce.

    Update: Dave has alerted us to an error in the graphic of his DIY Swirl filter illustrated above. The Water Flow inlet pipe into the blue barrel should be at a lower level than the outlet pipe. The graphic has been fixed.

    “Just one small error is that in the diagram of the barrel where you show the water outlet at the bottom of the drum going to the growbeds. In my filters, the water outlet is at the top. The water from the fish tank is pumped into the drum about one third of the way from the bottom of the drum.†said Dave, “Most solids then drop and settle at the bottom of the drum. Lighter suspended solids are trapped by the filter foam in the basket at the top third of the barrel. Clean, clear water passes through inside the basket and foam. Some biofilm also forms here as there is very little water movement. A 40mm ball valve is opened a few times a week or more often depending on fish density.â€



  2. DaveOponic

    DaveOponic New Member

    Jun 13, 2009
    Thanks for re-posting this. I think Castaway is the original author based on some photos and notes I sent him on my swirl filters.

    I have three of these swirl filters that I have made and have been using for a few years now, with few modifications.

    Quite a few people have asked about them, so good to see this passed on to others.

    An equivilent sized commercial filter would cost hundreds of dollars. These filters can be made for under $ 50.

    I'm not saying it is a perfect solution, but for DIY'ers like myself, doing AP on a budget, the filter works very well.

    One improvement I can suggest is to fit a non return valve on the inlet pipe so if the power goes off, the water from the barrel does not flow back to the FT. I haven't done this but will soon as I plan to add a timer, due to some water logging problems.

  3. Aquaarche

    Aquaarche New Member

    Oct 26, 2011
    I am working with this type of swirl filter but it takes a lot of work to clean it without a valve on the bottom to flush the tank.

    I will be working on a vortex filter system with a funneled bottom solid tank w/cleanout valve, a fine particle filter and then the ammonia bead filter.

    this will work with gravel bed like what Murray sells, IBC, float troughs, hft or any other type of system. the idea is to keep the waste out of your gravel and grow beds altogether longer life for your gravel or other medium.

    the vortex filter can be flushed easily everyday, the most work is cleaning the fine filter but that will be limited to how long it takes to clog/plog and hinder water flow, the Ammonia filter will only need cleaning once in a blue moon (when cleaning do not use tap water treated with chlorine or other chemicals) as it is a bacteria filter to convert ammonia to Nitrite and that to Nitrate.

    Anyway as soon as I get some free cash I will start a IBC system first a step up from my current system. this is all preparatory for a larger system for a training program for newly released prisoners.
  4. watercat

    watercat New Member

    Nov 14, 2011
    I had always thought a simple low speed centrifuge would be ideal. Run on a timer and with some sprinkler control valves it could be self cleaning. Just add a few minutes to the timer until you get the results your looking for. I use to have centrifuge for my waist oil and it sure cleans stuff right up in a hurry and in one pass.

    I have a small low speed honey separator for my hive boards i built from a washing machine motor and a plastic barrel with a 5 gallon bucket inside it for the centrifuge bowl or the unit that holds the hive boards. It seems up to a low rpm of 200rpm or so but that is just pulley sizing of course. The 5 gallon bucket has drain holes drilled in it. The honey is pulled from the comb and then runs out the bucket into the drum where it is drained through a tap into jars. Very slick and very cheap compared to the commercial units. In fact its at a commercial operation right now that is using it to see if they are going to build several and start doing processing right in the fields instead of bring it back to the shop.

    don't think i have $100 in it and its cheap to run. I can see this filtering fish i can also see posts of people that have already done this but i have not read any yet.

    This is how i would adapt for fish filtering so that the waist can be harvested as well and sold or used.

    a poly 55 gallon drum mounted above the FT water level. a pilot bushing or bearing installed in the center bottom of the 55 poly drum.

    A drain valve installed on the bottom of the drum.

    The drum would have its lid removed or cut open.

    A 5 gallon bucket would have 19mm shaft flange (pillow block) bolted to the bottom of the bucket. the stainless shaft would travel from the 55 gal drums pilot bearing through the bucket to the top of the 55 gal drum. across the top of the drum would be mounted a 19mm square tube with a pillow block to hold the upper shaft. just above this pillow block is a vee belt pulley.

    There would be a electric motor 1/4hp or 1/3hp bolted on a bracket that was attached to the drums side. allowing a jack shaft that was part of this bracket to be run to reduce the rpm to the shaft going up that would hold the pulley that is lining up with the pulley on your 5 gal buckets shaft.

    Unless you have giant pulleys you have to run a jack shaft. i had to on my honey unit. Its actually all fairly small and compact and there is no reason to believe water would get on the motor plus it could be shielded to make sure.

    The bucket in the barrel would be able to have very simple angle metal or plastic bolted to it or riveted up and down around the inside for the collection point for the waste. You could go with lots of angle or taller angle but both would work.

    I like the idea of drilling say 25mm holes in the sides of the bucket at the bottom of the bucket. running a pvc pipe fitting from there to the center into a simple pvc tee. and running it up the center of the bucket to its ideal drain height.

    so your FT water is pumped up in dumped in the 5 gallon bucket all the time. It fills up then drains to the 55 gallon drum its in and flows out the bottom via a valve or fitting.

    when you choose depending on your fish density the timer or ph tds meter activates the relay that turns on the electric motor. the bucket starts to spin and the solids in the bucket now are pushed out to the sides of the bucket and lodged in the angle material. being the solids weigh more than the water the bucket only allows the water or the lightest material to be in the very middle of it where the over flow drain is. the water is siphoned out and runs down in the bigger drum that is collecting all the spray from the smaller bucket spinning and letting its water out from both sides. The now cleaner water flows out the bottom of the barrel and can be directed any where you choose.

    I am planning on making it self cleaning with a couple sprinkler control valves and barrel on the ground for the waist to rinse to so it can be used out side the green house. this also allows the system to operate with out you tending to it or allowing the solids to be washed right back in.

    I'm not so good with the descriptions. but if you you tube a simple centrifuge you see how basic the idea is and making it self cleaning is not all that hard. my stems are all automated so trigger would be done with my tds or ph meter i believe. this is how my hydro system works now for basic flushing of the system or as that goes adding nutrient or buffers. I'm going to laugh if most of you have one. its probably kinda like a swirl or vortex system but way more effective or controllable because of the speed and quality it can clean to.

    sorry for it being so long winded and my run on sentences.

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