Backyard Aquaponics
A place to discuss aquaponics

Guys

Started my build of a larger system, 2 x 2k Poly master tanks, 8 x BYAP GB's and a common DWC raft.

Just need a sanity check on my pipe size which will be "gravity feed" through the RFF - Bio - GB's then DWC. The Laguna pump will be in the DWC raft and pump back, splitting the volume between the 2 tanks

I have 65mm outlet on the bottom of the tank. Im not doing SLO but a 50cm x 100mm riser from the bottom closed of at the top with a heap of holes in it so it will suck down. The height will be governed by the height of the RFF. As above, i will run these independently so its own FT - RFF - BIO and row of GB's. This will allow me to isolate lots of possibilities for maintenance, cleaning etc

Soooo - pipe sizing through this part which is gravity fed. 65mm DWV is quite expensive so im looking at 50mm. The 2 runs of 50 will be run next to each other in the DWC part. I know there are systems out there with this easily, just want those who have experience with this type of sizing to advise if i can use 50mm, keep the runs as straight as i can and instead of 90 angles, do things like 2 x 45 to minimize friction loss. It will have the 2k per hr running through it

Thoughts?

ohhh - and Happy Easter all

I run about 2klph through one 50mm pressure pipe SLO OK. It all depends on how much freeboard is in your design. You will be locking yourself into constant flow though.

Hi Erich sorry I didn't say it earlier but welcome to the forum.

Couple of extra bits of info:

Which Laguna have you bought to be your pump? Need to know that so we have an idea of the flow.
Is the DWC going to also act as your sump?
If not are you happy with constant flow and constant flood in your GBs?

Hey

Welcome? Been here for a few years :p

CF - I will be doing constant flow on all GB's so as they run into the DWC, the height wont change. Yes - the DWC will be the sump and pump back to the 2 x FT and split 50/50.

Just measured, have max 1 metre head (from top of water level on DWC to inlet on FTs). Its a 12 mth old Laguna PT 8248 (i bought a heap of "The Hopefulls" gear)

Each "run" will go into its own 100 litre RFF then 200 litre Bio moving bed filter then gravity fed into GB via taps

Freeboard as in height to GBs from outlets of RFF (that will govern the height of the FT level) and Bio - plenty. Have 20 to 30 cm easily

I can throttle the pump down as its a 9,000 litre (with zero head) as long as im doing "at least" 4k an hr for 1:1 turnover. The run back to the FT will be about 10 metres straight

Some pics may help

lol - its all good

Your description of the cover of your center drain sounds a bit odd. The great thing about using an AQ tank is that it is very easy to get it to concentrate the solids in the center so that the center drain can remove them. If the holes in the drain cover at the top how are the solids going to get along the floor of the tank and then up the side of the pipe and then down in to the drain?

Because you were talking about isolating beds I assume the beds are to be plumbed in parallel not in series?

Since you have been around for a while I'll assume you have a good reason for wanting a RFF but why the bio-filter?

If there is a 1m vertical lift then without friction losses (get to those later) flow should be less than 6800L/hr.

Hi Erich, From your drawing the FT height is being set by the RFF inlet not the outlet, You need to lower the height of the of the inlet. Can be say 150mm lower than the outlet, after all you are going to have a large pipe over the inlet to make the water flow change 180 deg.

On the pipe sizing I use 50mm DWV (because its cheap) through my RFF and Bio.

May not have explained myself properly - i do that :/ I did mean it has a blanking plug on the top. This will also be the outlet to the RFF - exact same thing Mantis has

Correct - my image etc are out, done it to quick

50mm is a good size, just want to make sure its fine out of the FT and also past the filters

Speaking of not explaining one self well (been a lot of that lately) so you have:

A. Two lines of GBs plumbed in series but parralel to each other; or

B. Two lines of GBs plumbed off two separate manifolds in series off each manifold.

In A a line of GBs can be turned off but not an individual GB

In B each individual GB can be turned off.

will this plan reduce the flow as its closer as there will be less travel now back to the FT's. I have options to close the head up some as well

In response to your post -

There are 2 sub systems - FT runs that run into a common DWC

I can isolate (have not drawn in valves etc) after the Bio on any of the 2 runs and i can also join the 2 runs together (if i went RAS style)and use it as RAS so i can turn of the first 3 GB from system 1 and/or last 4 on system 2 or i can turn of System 1 totally or system 2. As they will have taps on them, yes i can isolate any individual. To isolate RAS style, there is additional pump in the FT - this will be done later on

Before embarking on the next step it would be a good idea to get an idea of the water velocity given the maximum flow of 6800L/hr.

V=Q/A

Where:
V=velocity=m/s
Q=m3/s
A=m2=Di x Di x 3.1416 / 4
Di=Internal Diameter=m

A50= 45.6 x 45.6 / 1000^2 x 3.1416 / 4
=0.00163m2

V50=6.8 / 3600 / 0.00163
=1.15m/s

V90SW= 0.32m/s
V100DWV= 0.27m/s

Using 50mm pipe from the sump/DWC to the FT will have significant friction losses. Using 90mm storm water won't cost much even if the run is long and there won't be too much loss. Using 100mm DWV will ensure even less friction losses but might get pricey for a longer run.

Your alternative design lessons the pump pipe but makes the drain pipes longer and more complicated. It is easier to reduce friction losses in the pump pipe by just making it bigger where as doing this on the drain side can be problematic. Although since the water will be highly filtered before going to the GBs may not such an issue.

Out of interest what are you doing with the solids?

You next question to answer is what size pump pipe you will use.