Backyard Aquaponics
A place to discuss aquaponics

On a 55 gal RFF, if I have 43 gpm coming in, what would be the best pipe sizing for correct retention rate? 3" or 4"? Also, would using a 3" inlet and a 4" outlet with either a ball valve or gate valve allow me to adjust retention rate in RFF without slowing down the flow to the sump that the pump starves?

PM Stuart Chignell

Thanks ff,I know him and Ryan would probably know the numbers off the top of their heads.

I know Stu helped Dasboot and Swede with their calculations for their RFFs.

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Are there "calculations"

I suppose anything can be reduced to mathematics, but NOTHING that I have built has been based on maths, and it does work..

Would calcs make a difference...? You have what you have and need to make it work..

The bottom line is that you want the inflow to be as gentle as possible, to create radial flow but as slow as possible..

I would over engineer by splitting the inflow to two inputs on opposite sides.. and I would add plastic baffles about 2/3 down the barrel, to slow the deep rotation, and enhance settlement...

I wondered how I would build one and thought of a plastic cone at about 2/3 depth, acting like an umbrella...and attached to the centre retrieval overflow stem..
The baffles would stall flow below the umbrella, allowing solids to slide down the drum wall..
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CC... this is the concept of what I plan - when forced into RFF..



Input would be from multiple inflows at the top, with elbows , pointing in the same direction to create the RF..

The baffles would be angled in the flow direction, to push the solids down with a small RFF component..

The inverted cone on the input to the outflow pickup, is simply to reduce the solids pickup from the bottom.. naturally the tube is castellated to allow inflow...

I can't see how you would use controls of ANY form as I assume that ALL the flow goes from FT>RFF>GB's etc. slow the outflow and it overflows.. slow in inflow and you reduce your GB turnover..


I suppose I would go for the largest outflow and the smaller inflow (but multiple jets eg.. even three 2" ).. ie you need to have the out velocity as low as possible.. IMHO
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No GB's just a RAS. The current RFF has 2" plumbing and it's to small to keep up with the drains. The water will rise in the RFF and then the FT's will start to slow and overflow. I need to increase the piping, but was hoping to not have to redo it AGAIN my making sure I get the sizing right. 3" & 4" valves and fittings aren't cheap, and I want to try and make this a 1 redo and done job. I THINK the 3" inlet and 4" outlet with control on the 4" side would work, but was hoping for a confirmation from someone.

All these acronyms and terminology... What IS a RAS, if not "Recirculating Aquaponics System"

http://orange.ifas.ufl.edu/uf_workshop/pdffiles/Fact%20Sheets/OCES%20Fact%20Sheet%201-13A.pdf

so there is surely food production and if such is a media bed or a flooded (DWC) , then it makes little difference...




so where is the pump..




Again I can't imagine how a valve will be used EXCEPT after the PUMP, which will then slow the total INPUT to what is acceptable by each serial component.. Slowing the pump flow will up the power consumption... Everything will depend on Angle-Of-Dangle, after the pump..





Unless I misunderstand, and the RFF is in fact sealed and not open, then you simply CAN'T control the outflow.. it has to overflow..
BUT - yes 3 in and 4 out is a good assumption, but split the 3" to say 3 by 2" actual inputs.. IMHO

This is a problem where multiple questions are asked away from the system thread, when the SYSTEM can be seen..

there is like 100 ways of doing it and likely 80 will work..
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Coach,

Google - Cornell dual drain design it will take care of your current problems. Basically it turns your FTs into individual swirl filters so you are only sending your dirtiest water through your RFF.

I have bottom and side drains, even though without aeration and not pressurized O2, the water coming out of top drains is not really that clean. The agitation form the bubbles moves a lot of solid "up" into the water column. The problem is with the side drains, and they still need to go through the RFF. I have the bottom drains on large tanks going directly into the shade cloth filter, but the juvi and fry are going into the other RFF and then into the shade filter.

BD- you can see the system on my RAS build thread: Coach Chris' RAS build. Sorry, don't know how to add link
No plants, just fish. Recirculating AQUACULTURE system.
RFF is regulated by air pressure and is controlled by raising and lowering the weir. I will increase the pipe size, just not sure what is the best size for proper retention time. I'll try and research the ideal time. There is a formula that determines the pipe size and flow rate to determine retention time. I just can't locate it yet. I know I can slow the flow down by increasing the outflow and using a knife or gate valve, I just don't know if the sizes are correct.

Hi Chris
KISS
As I understand it;

1 Max distance between inlet and outlet
2 Be gentle with fish poo. Don’t break up big bits
3 Flow separator divides RFF 1/3 2/3rds
4 .100 ish micron efficiency at best.

Fish poo flows up pipe. Then reverses and flows down.
Gains potential energy flowing down due to increased mass.
This is greater than the up flow so fish poo continues down.
So logically, slow speed outflow big pipe.

Remember if you are flowing a lot of water through your RFF you may have to upsize the entire RFF (container included) to get the needed retention time. There is a great chart on this thread that may help you decide how to go from here. http://www.koiphen.com/forums/showthrea ... tler/page3

Thanks guys. FF, that's the chart I was looking for. Everything look good once I upgrade the pipe size to 3". The stilling well may be a bit small, but that's an easy fix If I need to change that. The 55 gallon barrel size is almost perfect.