Backyard Aquaponics
A place to discuss aquaponics

LOL, you gota pre filter

A 7.5 inch funnel from northerntool.

Convert a swirl filter to a FSB

Here is a link to a real simple Fluidized sand filter. If you use coral sand it will also help with ph when the system goes acidic.

link
http://www.duboisi.com/diy/BNfbf/bnfbf.htm

Robert

That's a good link Robert, but isn't styrene dangerous to fish, it certainly is to humans if it leeches into the water?

I'm sure some pipe available is or can be harmful if it leeches into the water. I personally would use schedule 40 pvc or some other potable water type pipe in this application.

I know of several people who use the type of pipe shown in the link for their saltwater setups and have thousands of dollars worth of fish at risk without any problems. Only thing is they aren't trying to eat their fish either.
So when in doubt err on the safe side and use pipe that is made for potable water use.

Robert

Good link Robert, another way to incorporate Dan's idea of increasing the cross sectional area as the filter height increases

A while back I ordered some LDPE and today I had some time so make use of it!

First I designed the cone I wanted to use for my FSB bio-filter using the cone layout software from the previous page of this thread..


Next, I printed out the pattern and cut it out. If you don't have a large format printer then the program prints it out over several sheet and you just have to cut out the pieces and tape them all together. This cone is 1.5 inches diameter at the bottom, 18 inches long, and 4.75 inches diameter t the top.


Next, I pressed the paper to the LDPE plastic and marked the edges


Next, I cut out the plastic piece using metal sheers; it was 1/8 inch thick


Next, I shaped it. It was a pain at this thickness, so I had to heat it in the oven some to be able to get it in shape. Then I baked it in the oven at 275 for 15 min to set the shape of the plastic.


Then, I used my harbor freight plastic welder and pieces of LDPE, cut from the sheet, for welding rods and I welded the seam together. I also cut out pieces for the top and bottom and welded them on along with some pieces to direct the return water back into the fish tank.


Next, I plumbed it in through a sedimentary filter.


Zip tied the input water line in place; just off the bottom


I Added 8 ounces (volume) of sand and I have a working Fluidized Sand Bed Bio- Filter. Total cost, not counting tools and $29 sediment filter, $3 tubing +$17 LDPE + $12 for the pump.



The sand does not come anywhere near being able to flow out of this cone! However I think I need a valve to slow down the flow of water so there is only enough water flow to just cause the sand to separate; for maximum bacteria growth.

My first attempt at welding LDPE is pretty ugly, but it works and I have enough material to make a second FSB for no additional cost. I learned that I should have bought the welding rod. Also worth noting is that there are no fumes from LDPE when heating or welding! LDPE is as food safe as plastic gets. However it can not be glued. I think it would have been more easy to use a thinner (.0625 - .03125 inch) sheet of PVC becasue it can be overlapped and glued in place; leaving the top and bottom as the difficult parts to attach.
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[flash width=400 height=359]http://66.76.55.66/naphtha/movies/fsb.swf[/flash][/align]

good to see ya experimenting dan!

watch that clear tube, i hate the way it collapses under its own weight i usually coil a piece of electrical cable around it and twist tighten

If you want to see the video of it on youtube:
FSB video on youtube

Dan, can you check that link - seems to be a strange FSB filter

also, can you advise on the flow rates you are using for that sized FSB

yes, i spent 30mins looking at plasma

That is inspiring Dan!

In your measurements, do you quote the top and bottom as circumference, diameter or what?

cheers

Looks like diameter to me.
Melting plastic can`t do your lungs much good Dan
over and above just taking one for the team i`d say.

What would the rough tank capacity be for this FBF?

Hex, there are not any fumes from welding LDPE or HDPE. As to the capacity of the filter, its hard to say because I just used play sand and not equally sized/graded sand. If it was all medium sized then based on the amount I put in it would have a surface area of 4,430 square inches/ 9.309square meters, enough to process 1.86 to 8.3 grams of ammonia per day in theory or based on the SRAC pdf, 2 to 10 grams of ammonia. I have room to add more sand, but that might make it unable to restart after being turned off. Southern Regional Aquaculture Center says 10g/day of ammonia is produced per 100 pounds of fish. So .1 grams of ammonia per pound of fish that would mean this filter can handle 18 pounds of fish with 8 ounces(volume) of medium sized sand and up to 36 pounds of fish with 16 oz of sand and a better pump. I have ~1.7 pounds of fish in the tank.