Donabbd,

First of all a good rotating drum filter is an extremely effective way to remove solids from a koi pond or aquaculture system. The good quality ones that are aquaculture grade start at about 5 grand. And they are extremely efficient as one I've been looking at uses power rated in watts. I saw 25 watts but not sure it that is continuous or only during a cleaning cycle. The specs are below Phil.

http://www.koiacres.com/koi-acres-products/rotary-drum-filter/kc-60-rdf-filter.html

Originally Posted By: esshup
What I haven't figured out yet (I haven't looked either) is how the solids that are clogging the screen that the nozzles wash off get out of the inside of the drum,...


There's a channel in the drum where the solids exit after the nozzles wash the solids into it.

Originally Posted By: esshup
...and how the nozzles determine when to turn on. They might be on a timer, or there might be a level sensor for the water level inside the drum.


You got it right. On and off of the nozzles can either be turned on periodically by a timer, or when the screen clogs enough for the water level to go up, a water level detector senses that and turns on the nozzles.

I will probably purchasing the unit above for my coldwater setup in the pole barn as 5 grand is a little out of my budget after all the other expenses. I'm basically doing the same thing as the koi pond people in that I am raising large high value fish at lower than food production densities. Densities have to stay below .25 lbs per gallon to preclude fin erosion on the trout. (Nipping and aggressive behavior). Wear and tear by concrete raceways is myth. It's nipping and biting of fins by fish that are in high densities as in raceways.

My plan is to use a DIY (RFF)Radial Flow Filter or Parbolic Sieve Wire filter for each 2000 gallon tank with final mechanical filtraton with a (RDF) rotating drum filter. Then the water goes to the bilogical filter of my choice, which would be an DIY RBC (Rotating Bilogical Contact Filter) , DIY MBBR,(Moving Bed Bioreactor) or DIY (Fluidized Bed Sand Filter) FBSF. Could also be a combination of the three as I have 3 RBC's at my disposal and MMBR's are really easy to build. I've also built a large FBSF but haven't used it yet.

I'm researching airlifts and if can move all the water via air that would be one heck of an efficient system.

The cool thing is most of these filters I can and have built myself to keep costs down. The rotating drum filter is above my pay grade and it's probably one of those things, when all is said and done, you're better off buying as someone else has already worked out all the problems.

BTW here's the RFF (Radial Flow Filter) that according to some studies I have read reamoves about 48 percent of the solids before the water goes to a RDF (Rotating Drum Filter). This reduces wear and tear and cycling on the RDF. And in case of problems the RDF can temporarily be bypassed.

http://www.earthangroup.com.au/diy-solids-filter/

The following DIY sand/gravel filter may be my best option to remove iron from the well water before it reaches the system. Periodical cleaning with a 1 hp blower or shop vac seems to be fairly easy.

Or it just may be a way to get some additional polishing. I have two barrels and a siphon that works quite well but not sure how well it will work for increased flows.

http://www.koiphen.com/forums/showthread.php?68132-Birdman-s-Sand-Gravel-Filter








Last edited by Cecil Baird1; 11/10/13 10:44 AM.
If pigs could fly bacon would be harder to come by and there would be a lot of damaged trees.