Rotating Drum Filters marketed for Koi ponds

[GaryD]

Hi,

While I wouldn't be without one if I ran a commercial aquaculture unit, I can't see what an RDF will do at the small end of things.....that a sieve filter won't......and for a fraction on the cost.

Gary

[Cecil]

Hi,

While I wouldn't be without one if I ran a commercial aquaculture unit, I can't see what an RDF will do at the small end of things.....that a sieve filter won't......and for a fraction on the cost.

Gary

How far down on the micron scale will a sieve filter strain?

Like I said in a previous post the following species of trout (actually a char) is very sensitive to particulates. More so than rainbows or brown trout.



One thing that attracted me to the rotary drum filters was how quickly they removed the solids from the water column vs. having them sit there before being removed, and all of the serious ras' for trout seem to use them.

[Cecil]

I have installed and operated both brands of those drum filters of quite a few sizes and they only go about 7% water exchange per day. Some of the larger ones will run around 10%. Really depends on the size of the micron. Lower than 40 and they will run water out excessively.

From a cost point of view in a commercial environment, I am not sure how anyone can do without them, especially if running a pure oxygen system. I have seen some plastic style cheap ones here in many fish farm graveyards. Recently, a farmer wanted to buy the smaller faivre one and they run out around 14k. He opted for the plastic cheap one for around 7k. Saved himself 7k then it failed 6 months later and lost 80k worth of stock and the following years sales value. Cost really is not an issue for what they do for production capacity.

Hey thanks for the great feedback based on experience.

Yes, I'm quite familar with the pay now or pay later dilemna. My father used to live by it because he grew up not being able to afford anything, and I found it really annoying. LOL On the other hand he is a natural engineer and can build and figure out just about anything because he had to.

Just curious what failed so cathastrophically on the plastic unit that couldn't be repaired? After analzying all the specs and pictures I can find on them, they all seem fairly identical and run and clean on the same principal. Even the electroinics are pretty much identical as far as either a water level sensor or a timer. I'm not a engineer but they don't really look that complicated. I've considering building one that instead of motor and chain is water powered like my RBC. Get rid of the motor and gears and use a water lubricated axle that is mounted in the center.

[GaryD]

Hi Cecil,

How far down on the micron scale will a seive filter strain?

For practical backyard purposes......about 150 microns. Coupled with a bag filter, they'll easily go as low as a rotating drum filter......about 40 microns - at which time, even the RDF will start bypassing.

As I indicated earlier, if I was producing commercial quantities of fish, I'd probably opt for an RDF, too.

Gary

[Earthan Group]

Just curious what failed so cathastrophically on the plastic unit that couldn't be repaired?

I am not entirely sure but from report from farmers with failed ones, the surface area is too small on the filters for commercial volumes of feed and the flowrates need to be backed off resulting in oxygen deficiencies and the resulting loss of growth. In this one case the drum simply stopped turning (assuming the belt and pully systems are not high quality) and the resulting build up of organics wiped the fish out. I have had no personal experience with the cheap versions but I tend to recommend avoiding the plastic micron mesh as it become brittle quickly and fails (large holes apprear). The housing can be plasitic or stainless. Generally those submerged in channels have no housing but ones runnign saltwater slab mounted use a hdpe tank.

A point of failure may be the plastic do not do well with the weight of bio and solids over time...

[Earthan Group]

They are a beutiful fish Cecil

[Cecil]

They are a beutiful fish Cecil

Yes they are and large ones are hard to find for taxidermy specimens hence the high prices I get for them. Brown trout are almost as hard to find and almost as lucrative. One of the reasons I'm considering bringing both species inside is less water flow required, more control of water temps, elimination of pathogens, better water quality, no predators, and biosecurity..

The browns are easier to raise though and can handle warmer temps. They explode in growth in my flow through trout.

[mortys]

Hi Cecil,


For practical backyard purposes......about 150 microns. Coupled with a bag filter, they'll easily go as low as a rotating drum filter......about 40 microns - at which time, even the RDF will start bypassing.

As I indicated earlier, if I was producing commercial quantities of fish, I'd probably opt for an RDF, too.

Gary

150 micron is very close to the limit. The best wedge screen available only has about 20% open area at 150 micron. When open area falls below 17 or 18 percent the water begins to follow the top of the screen instead of flowing through it.

[ande]

Hi Cecil
This might be a contender/option, for you ? Here is a link to see the self cleaning of the new oase drum filter, with lid off.
http://www.youtube.com/watch?v=j6Nmu...ature=youtu.be

Spec. here
http://www.oase-livingwater.com/zh_C...zsproducts_pi1[product]=6694&cHash=6ad1d25c96b83c72bafd2936fb46c402

cheers

[Cecil]

Hi Cecil
This might be a contender/option, for you ? Here is a link to see the self cleaning of the new oase drum filter, with lid off.
http://www.youtube.com/watch?v=j6Nmu...ature=youtu.be

Spec. here
http://www.oase-livingwater.com/zh_C...zsproducts_pi1[product]=6694&cHash=6ad1d25c96b83c72bafd2936fb46c402

cheers

Andy what are the price ranges?