Tilapia by the barrel

[Hal Hurst]

I set out probably a year ago to see if I could raise tilapia in a series of 50-gallon food grade barrels.  I have been tinkering with the setup and now I believe I have reached a point where I can start to consider adding some complexity to my system and incorporating some aquaponics. I am joining this community to pick up some tips and discuss problems as I begin this process.

My aquaculture setup as it is consists of three barrels arranged in steps.  Water flows in series through two barrels which are used for habitat (with space for adding another) and then to a biofilter barrel.

The #1 tank contains the adults.  A 1 1/2 inch outlet leads to the #2 tank, where juveniles are swept due to water currents. The #2 outlet is protected by a fine screen and leads to the top of the biofilter: first a 24" diam x 4 inches thick polypropylene matt filter, then two rolls of polypropylene/ calcium carbonate ribbon, with a 24" aerator disk through the water flows. 

In the bottom of the barrel are the pumps:

One water circulation pump cycles water from the bottom to the top for an extra pass through an aerator shower and back to the top of the biofilter.

Three redundant waterfall pumps lift the filtered water about three feet to a 1-1/2" fresh water supply pipe, which returns water by gravity to tank #1 through a manual valve. This water line also has taps to access water for watering plants, and for another 45 gallon glass fish tank intended as a breeding tank.

One pump lifts the water 12 feet to a solar collector for heating; this is controlled by a switch which enables the solar heater when the collector has reached a high enough temperature, and a thermostat to shut off the pump when the habitat reaches the desired high temp of 95 degrees. In addition there is an electric heater which ensures a water temperature minimum of 70 degrees.

Another collector pipe collects the solar heated water and returns it to the aerator shower and top of the filter. There are provisions to accept other return water inputs, such as water from a remote breeding tank, not fully integrated. 

In addition to the barrels previously mentioned, there is a make-up water barrel, which collects rainwater and/or dechlorinated tap water, and supplies water to top off the system when water is removed.  Another separate barrel is used for conditioning tap water and collecting excess rainwater runoff.

I routinely draw off water from the system to water my container garden.  This is a series of soil-based planters, and there is no collection and return of water that passes through them.  I also have a worm compost bin.  The entire setup is contained in my patio, which is roofed and enclosed with transparent polycarbonate to extend the growing season, so all lighting is natural and subject to seasonal variations, such as there are in Southern California.  This is OK with me, I think I can live with these limitations.

This is my system as it stands.  I am now considering appropriate plantings in hydroponic beds for veggies both summer and winter.  I want tomatoes, squash, snow peas, green beans, root vegetables, sweet potatoes, herbs, and greens, and I can choose the ones that lend themselves to the medium best, using conventional methods for the rest. Now to see what I can learn.

[wer winn]

Hey tallim rocks or almost any inert material with a LOT of surface area will work. Stuffed full of Netting, (Bird netting is probably the cheapest.) Nothing about doing this is inexpensive, (Either use $ or use your labor.) Moving gravel out of drum to clean it is not something that I would look forward to. Old fishnets or the cheapest netting one finds online is what I think would be the easiest for you. If you live in an area that has swamp coolers, a roll of the replacement cooler pad material is not too expensive, relatively. Maybe start a thread up called inexpensive biofilter? This blog is not a high traffic area.

Best of luck in your searches.
werwin

[tallim]

I am setting up a 55 gallon plastic drum for a biofilter could anyone tell me what to put

in the drum not the expensive matting. any other material sand stones etc. thanks

[Hal Hurst]

wer winn: I am using one brass check valve and the rest plastic.  Check valves can fail if the water passing through is chunky and a particle lodges in the sealing surface just right. For this reason I want to use a fiber filter at some point to remove stuff like duckweed, plant detritus, food particles, and fish poop before it gets into the valves and the pumps.

[wer winn]

Hal,
Think the redundant pumps are a great feature. Thanks for the quick response, and advice. I have had American made brass check valves stick open. Specifically looked for the best.
A tap on the top of the will generally free them. I now put them in with a union on both sides, (for easy disassembly). My experience comes from off grid water systems here in the SouthWest where our water is 'rich' in minerals. When they are off and free I can usually shake them, and free up the action.........JustMy2Cents.

Thanks werwinn

[Hal Hurst]

I am getting my supplies from Home depot, with used food-grade  barrels from the surplus store. The pumps are common waterfall pumps of various sizes. I use a super luft pump for air, and I have routed the air through air stones contained within 1/2" pipe for circulation in barrel #1  and [1/4' soaker hose intended for drip irrigation, wired in a spiral to several 24" disks of 1/2" coated wire mesh].  these disks are at the bottom of the biofilter, above the various pumps that distribute treated water: two for water return, one for solar heating, and one to recirculate the water to shower on top of the filter for a second pass.  The water is also aerated by water action as shown in my post to another forum here, as it enters the habitat.

I would use your 225 gallon tank if I had room.  It is said that it's better off to start with a big volume, and it would be easier for me to see and work with the fish.  My biofilter is a lot bigger than I have sen elsewhere in this site, probably because I am not using growbeds at this point.  But I am using 2 spools of springflow filter medium and  two two-inch thick x 24" diam  disk of layered scrub-pad type fiber mats as a pre filter.

Why redundant pumps?  One equipment failure in this system could be catastrophic.  The fish would quickly suffocate. And I have had pumps fail before.  If using pumps in parallel don't forget to use check valves, to prevent back flow when the pump is not operating. I try to have at least one or two total system volumes flow through the biofilter every hour. The recirculating pump within the biofilter is a cheat to get that, as well as returning the solar heated water upstream of the biofilter.

Why barrels?  They fit into my available space.  I would much rather have a larger tank.  A barrel might be good for smaller fish until they are too big to be eaten by the larger ones. And I have been wondering if I could convert an old hot tub to serve as a fish habitat- they already have pumps and bubblers.

[wer winn]

Hal,

Really like your system lots of questions.  What pumps do you like? Redundancy with multiple pumps. I like it! What gave you the idea? Air pumps types, volumes. did you make your own bubblers?  What would you do different if you had a fresh slate?  I have room for an IBC, (about 225 gallons).  Would you use one as a first tank and then drums or start with drums in a newbie system. 

Thanks werwinn

[Hal Hurst]

Oh Shucks- I forgot which post I was replying to.  For more pictures see the member systems introduction forum.

[Hal Hurst]

@ bartman: don't know what vacuum tubing might be- I'm using 200 feet of 1/2"  black polyethylene tubing arranged as in the picture I hope to post here.  My transparent roof is held up by five 16 foot 2x8s.  span is approx east and west, so one broad edge is facing the south.  On each southern edge, then, I have placed four passes of this tubing, and each joist is about a foot lower than the one above it, so once the water is lifted to the highest joist, the whole thing drains by gravity back into my biofilter.

Pictures: Upper left: the test fitting showing plan A water flow. Upper right : black tubing on a black painted redwood 2x6 surface, Lower left: tubing partially reinstalled with new flow pattern. Lower right: the final fitting to switch from single to 2 parallel flow paths (less resistance) You can see the polycarbonate roofing also half installed. Because the irrigation tubing did not have a full complement of the fittings I wanted the junction was a plumber's nightmare, But who's going to see, am I right?

I am not too sure about the efficiency heat exchange taking place- so many variables like ambient temp, cloud cover, etc; but on a sunny day I can raise the temp by 10 degrees by noon, in a system containing 150 gallons. And the collector is usually cycled off hours before sunset.  But note that all my barrels are insulated with 1/2" styrofoam wrap. 

[Bart]

Sweet sounding setup Hal, I'm curious what you are using for solar collector - vacuum tubing style? How large it is and what kind of a temp change it can make on your system in say three hours of straight sun light?

More pics is always a good thing :).