Backyard Aquaponics
A place to discuss aquaponics

I'd put it before the GB - the RFF will not get all your solids/fines so the GB backs it up. It will keep your GB cleaner and you can use the removed solids in a mineraliser and so add back many of the trace minerals and elements to the FT as well as have a fine fertiliser for your garden.

gday all
i found this clip i thought it may help the do it yourselfers
http://youtu.be/mKWXkf9j5Qc
cheers b&v

Rules of thumb for RFF design:

- Surface loading rate: 4.6 GPM/square foot of settling area.
- Stilling well diameter 25% of settling area diameter

Wish I'd found this post (I did do a lot of googling and searching on this site before building mine), but a lot of answers that I guessed would have been answered.



Has worked a treat though!


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Hello I'm a mino here!
Saw this tapered bottom filter in this post and I'm wondering where it can be bought?
Raskel311 posted the pic.
He mentions it as a cost of $50.00!

It's called a cone bottom tank, inductor tank, or conical bottom tank http://www.plastic-mart.com/category/19/cone-bottom-tanks. I didn't notice where he mentioned the size but for $50 it would have to be pretty small. They can be found online and sometimes at fermentation shops. I'm not sure what you have to ask for when you want the drain equipment on the one he pictured.

For a standard 50 GALLON drum/barrel, how far down does the downward deflecting pipe / bucket need to go? Is too low (4 inches off bottom) not good? Also, how big does this downward deflecting pipe need to bee in relation to the RFF inlet?

I ask because I have RFF with a 4 inch inlet, 6" downward deflecting pipe about 4-6 inches off bottom and seem to see a lot of suspended solids. Not sure if the deflecting pipe is too close to the bottom disturbing what has settled or if the flow is too high. I'm currently flowing about 500-700 gallons per hour.

Thanks

Lmannyr, there is a rule of thumb for the stilling well/baffle, The diameter is a third of the diameter of the surface of the RFF and the the length is a third of the water depth in the RFF,I have worked to this with good results in my RFFs,of course it is always flexible on these dimensions.
Retention time is fine...

Thanks for the replay DB

My baffle was 24 inches. I cut it down to 1/3 the height of barrel and it seems to be running cleaner at the exit. Need to filter more though. I have alot of fines exiting the RFF and entering the net tank. Still some fines exiting the net tank too. Wondering if packing more net into the net tank will help or make this worse. Or just make another filter tank...sigh

I run two net filters in parrelel,I find straight after cleaning I get a very small amount getting through but then as the bio film gets established again the water runs clean,I pack mine quite tightly,it's that sort of amount it's getting difficult to keep it down,I clean one one week the next week the other,I do open the drain valve daily and let it run for a minute or two depending on what comes out. I am pumping approx 600 gph through the pair of them.

gday all im giving away my diy filter too who ever would like it ...pick up from south east melbourne.. just pm me

Bringing this back to life.
Loads of great info in this thread!
Going to build an RFF for a DWC, hybrid system I'm working on.
Fish tank has in a SLO, which presently enters into a media growbed with hydroton, then from there it flows into the DWC troughs. Still getting a lot of solids in the troughs.
Going to put the RFF so the SLO from the fish tank enters the bottom of the RFF and bends upwards. Does the top of the inflow pipe have to be equal to or lower than the level of the fish tank, or can it go higher ?
I also see some designs with the outflow pipe exiting near the top of the RFF barrel, and some exit lower down. Any reason?

you have solids in your bed that will keep getting through, an RFF will help in the long term, but when running DWC / NFT it is a good idea to have a fines filter before it, even if you are using beds too.

The top of the RFF inflow must be lower than the water level in the FT and the outflow of RFF must be lower than the inflow of RFF.

Space is limited. Only really have enough space for one filter, between the FT and GB. Was thinking RFF to remove the bulk of the solids before the bed, and the bed would take of most of the reminder, and whatever solids got through that, would settle in the troughs.
Would suggest a Fines in place of the RFF in this scenario?

Your inflow on the RFF will both have to be equal to or lower than the water level in the FT, or it'll set a new water level 'upstream' from it - in which case your FT water level will rise to match it. If this won't cause an overflow it might be fine.

As for the positioning of the outflow pipe on the RFF, generally if it comes out of the barrel low down there'll be a length of pipe going up inside the RFF, raising the height at which the water actually overflows to exit. Again, the height of the outflow will set the water level 'upstream' from it, i.e. inside the RFF, and if it's much lower than the inflow then the water coming in will 'waterfall' down kinda hard, stirring up the bottom of the barrel and stopping it from working properly. To be effective, the RFF relies on the water in the bottom half of the barrel moving very slowly and gently.

I'm building one right now and I'm going with the inlet to the RFF being lower than the water level in the FT, and the outlet from the RFF being slightly higher than that (but still lower than the FT level).