Backyard Aquaponics
A place to discuss aquaponics

So I have most of the materials, I'm just running through my mind different ways of putting them together. I've attached a rough sketch of my plans. I was going to add some of my smaller (5") tilapia to this system. The water from the fish tank will be pumped through 1/2" pipe to a 120 gallon prefilter filled with 3/4" gravel on a continuous flow to help remove some of the particulate from the tank. Water depth will be about 8" deep and gravel depth will be about 12" deep. The idea was that the plants and worms in the continuous flow prefilter would keep most of the larger chunks out of the ebb and flow tanks. This tank would also have an additional drain on the bottom for periodic complete draining to wash out the particulate from the tank.

The water will gravity feed through 1 1/4" pipe to three 6' x 10' x 12" plant tables using bell siphons (with snorkels) to ebb and flow the water. I was hoping to have all 3 bell siphons draining to ONE 2" line back to the fish tank.

I know the tank order looks funky with the prefilter on the left and the growbeds on the right of the fish tank, but I was hoping to keep the prefilter on a small concrete slab that is in the shadehouse.

I guess my biggest concern is how much fluctuation on water level will I get with the 3 big ebb and flow growbeds.

Let me know if you think I'm missing anything

T

I don't think water fluctuations in your fish tank will be your greatest concern...

Your biggest problem is probably going to be ensuring enough water volume through/out your gravel filter... in order to get your siphons working reliably...

You might be just a well off putting a radial flow filter on the pad... and using the 120 gallon tank as another, deep. grow bed...

Bell siphons going into one pipe can be tricky. It helps to leave an air gap around the pipe as it goes into the one pipe, but you have to be careful that the flow does not shoot out of said air gap. 2" might not be enough to handle all siphons firing at once. With 1 1/4" inlets, each outlet should be sized at 2 1/2" then you need to upsize the pipe that they tie into so that it can handle the flow of all 3 at full flow, which is what you get when siphons are firing. Study up on the plumbing a bit more before committing on the pipe sizes. Also look into the Affnan siphon. Mine have been running reliably for some time now.

I am paranoid so maybe no one will agree with me but I would have an overflow on that high up 120 gallon gravel bed returning to the sump just in case of blockages or something

I would also go with a minimum of 40mm pipe to beds and for returns

I use 40mm on mine and only put about a 1000L/h through it and it is CHIFT PIST.. the 40mm only just handles that flow

so are the grow beds media filled? if so why not use them as filters straight away? if you put all your solids into that gravel 120 gal filter thing you may overload it and gunk it up quickly and then you will need to dig it all out... i think as Rupe said if you want to pre filter then use an RFF... way easier lighter and you can empty it to see how much gunk builds up..

+ you can have the RFF lower down and reduce the head a bit and get more flow for a given pump size.

If you swap the positions of the Fish tank and the sump and pump from the sump to the tank and then gravity flow from the fish tank to the beds you will have a constant height in the fish tank.

or just get rid of the 120 gal tank and just pump FT --GB --> FT

It may not be easy to raise a 650 Gal fish tank though.. depends on his setup I guess

true another alternative is to dig in the sump below the tank and pump from there.

Thanks for all the input!

The easiest thing to do would be FT to GB to FT, but I just thought some type of prefilter would be nice before sending the water and solids to the grow beds. The idea was that once a month I could open a large valve at the bottom (1 1/2" pipe) to quickly drain the 120 gal tank and any collected solids with it.

I have thought about putting a RFF filter (same as a swirl filter???) in at some point. I would probably use a 55 gal barrel and have it drain to the grow beds on the outlet.

In answer to Toms question the grow beds would be media filled (3/4" gravel) .

The tank is about 24" high, the grow beds will be 30" at the bottom and 12" high so the outlet for the RFF filter would have to be about 45".

Yep that will be better...now if only you could raise the FT and add a sump it would be perfect! Because then you wouldn't chop up your fish waste with the pump before the RFF and you could use a SLO from the fish tank to BGs instead... no pump clogging up either then

That's what I've done here, Ronmaggi's correct about the flow shooting out the top... This system does work but I have seen some spillage over the top a couple of times, I'm going to find something larger in diameter for the "manifold" and then I expect not to have that issue again.

In that situation it is worth adding a riser down the track that is open to atmosphere, it will assist the flow of air through the drain.

+1 pumping to the swirl/radial filter will reduce its efficiency because of TSS size, radial would be better than swirl,in my opinion,