DIY drum filter
  • stingsting September 2012
    Posts: 5
    Hi all koi hobbyist, I m newbie here. Would like seeking sifu2 otai2 give some comment & advice.
    Anyone use drum filter here? I want trying DIY filter on 55 gallon drum but dunno which is better a way. My filter going to place above the pond water level. Water is pump feed directly to filter, then gravity flow back to pond. Due to limited space, so I don't have any mechanical filtering for solid waste. Dunno how to figure out to put this because my place only can fit one drum filter only.....
    Here is my sketch drawing of filter:

    The media I have now is Japan Matt, bio ring, coral chips (2cm above), coral sand (app 0.5 to 1cm).
    1. So in drawing filter, which one is working better?
    2. What is the sequence of the media (1,2,3,4) accordingly for selected filter?
    3. What else must needed that I miss out?

    Really appreciate whose can contribute here......Thank you very much.
  • ChengAunChengAun September 2012
    Posts: 925
    I prefer B. The leftover fines can settle down at the bottom better hence better flushing and prevention of buildup of aenerobic bacteria. Plus you will benefit from the submerged uv light rather than if you want to use a uv filter tube.
    Be updated in the world of koi. Jangankan seperti "Koi di bawah bottom drain"
  • grinkz01grinkz01 September 2012
    Posts: 530
    filter a is better..easier backwash yet u will not experience water overflow easily caused by filter clog..while in b ur filtration will not fully effective as time goes by due to top part of filter media will get clog easily.

    u can also adopt similar uv system to filter a.
    Post edited by grinkz01 at 2012-09-01 09:12:03 pm
  • HDCuHDCu September 2012
    Posts: 1,117
    Hi Sting,

    As per your drawing, both design of the drum filters is difficult to clean especially since you want to use very fine coral sands which will block very quick. The other problem is the flow tracking of water where water will just flow to a straight path toward the pipe leading to the return to pond. This will make the effectivity of the filter not maximized.

    If you still prefer a drum filter, a possible design is to incorporate a mechanical filter in the form of pull out brushes placed vertically inside and around an eight inch pvc pipe place in the middle of the drum filter where the incoming water pipe is located. The 8 inch pvc pipe is supported and by smaller pvc pipes and epoxied sealed at the bottom to prevent water from escaping to the biological filter area. A drain is located at the bottom center of the drum filter to drain waste that will get trapped in the brushes( when you shake the brush up and down the detrius will fall down. You can also use static K1 as mechanical filter which you clean by air backwash.

    As the water travels up the mechanical filter(inside the 8 inch pipe), it flows out ward the pipe and into the biological filter area where you can place lots of dynamic K1 which are mixed by heavy aeration. There are two pipes 1.5 inch with valves located at opposite near the bottom and placed at opposite sides of drum. A service drain can also connected using a T joint. It is important that the water level in the mechanical filter area is slightly higher than the water level in the biological area so you can achieve a proper up and down water flow.

    It is important that the static K1 or filter mechanical brushes be cleaned onced in awhile depending on your feed rate.

    For UV you can just connect a commercial flow through UV to the return pipe to pond.
    Post edited by HDCu at 2012-09-01 10:10:39 pm
  • stingsting September 2012
    Posts: 5
    @ ChengAun, grinkz01
    Thanks of your input.
    @ HDCu
    Thanks a lot with your good explanation & suggestion. Sorry I can't understand this "There are two pipes 1.5 inch with valves located at opposite near the bottom and placed at opposite sides of drum. A service drain can also connected using a T joint". If have similar picture to show that would be great.
    Here I attach with new drawing.
    1. Which one is correct way for up down water flow?
    2. Is air backwash necessary in the PVC brushes compartment?
    3. Is static K1 = beads function (floating type)?
    4. Is Japan matt still needed?
  • HDCuHDCu September 2012
    Posts: 1,117
    Hi Sting,

    1 and 2. Your drawing D is close but not quite. It is better to put the incoming water pipe in the center of the 8 inch pipe so that you can put several brushes around the incoming water pipe. The drain of the 8 inch pipe is at the bottom of the 8 inch pipe. If you are using brushes, you dont need to put any air. Just by opening the drain and the incoming water pipe and by sloshing the brushes up and down, you can clean the brushes easily. If you are going to use static K1, then you would need air to backwash. You would need to put a net on top of the 8 inch and on the drain exit if you are employing static K1 or else there will be spill over. The is no need to put a outgoing pipe for the 8 inch pipe as water will spill out around the edge of the pipe and into the dynamic aerated k1 which will act as your biological filtration.

    3. static K1 is just k1 media but its not move by air. it serves as a mechanical filtration.

    4. Japanese mat is not needed anymore.

    With regards to why I mentioned two pipes going to the pond is that with two pipe going to the pond you have better water circulation for your pond while you avoid tracking of water in your biological chamber.
    Post edited by HDCu at 2012-09-03 01:14:03 am
  • stingsting September 2012
    Posts: 5
    Thanks HDCu....
    WTA, what is the best flowrate turn over? Feeding 1x per day, 5 koi size 1ft, 8 red parrots size a hand palm, pond 500gallon.
    Here I update new drawing for the filter. Can T joint connected as per picture at water return?

    Beside, this type of drum filter, any others design diy filter that @ low cost, easy DIY/maintenance & good filtration that you can recommend suitable for small pond?
    Thank you very much.
  • megatronmegatron September 2012
    Posts: 832
    I will propose your incoming water shall flow-in like a vortex flow so that the waste can settle at the bottom center.
    Don't ask me why!!!
  • HDCuHDCu September 2012
    Posts: 1,117

    Bro Sting,

    It is better to have two return pipes with valve from the drum filter instead of one bigger drain and split into two. The reason is that the flow of water in the biofilter will be more even while you can circulate the water in the small pond better.

    Also if its possible, its better to put a stand on the drum filter so you can put the big drain pipe at the bottom of the drum. if its put on the side, usually detrius cannot be flush out. Over time, the detrius become more and more sticky and will breed bad bacteria.

    Since your pond contains 1,900 liters, get a pump that can pump around 1800 to 2200 liter per hour which will give you a filter retention time of around 5 to 7 minutes and a pond turnover of once an hour. Since I assume you may not have any bottom drain, I would also place an underwater low wattage wave pump so as to circulate and push any detrius towards the pump.

    The above drum filter design looks complicated but its actually very simple to make and very easy go maintain. There is a mechanical filter area and there is the biological filter area. Since japanese mats are usually cut straight, the mats are easier to use in square of rectangular filters but are difficult to clean in drum filters. Moving bed K1 on the other hand also has lots of surface area for bacteria to grow and are self cleaning when air is introduced.
  • stingsting September 2012
    Posts: 5
    @ megatron, thanks for suggestion. Will do this...
    @ HDCu, thanks for explanation.
    Today visit hardware shop to buy the stuff, found out got 8" & 10" pvc pipe & end cap as well. So got ideal construct filter using 5 or 6 pcs pipe, cut length 3ft each. Then all connect with joint/bulkhead fitting (from up to down), each pipe have individual drain. This diy look like have more function on water flow up down filter. Any comment?
  • megatronmegatron September 2012
    Posts: 832
    This is how a vortex drum look like. It will be easier to have 2 drums if the space permitted. 002.jpg
    Don't ask me why!!!
  • stingsting September 2012
    Posts: 5
    Thanks bro megatron. Good pics.....

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