Backyard Aquaponics
A place to discuss aquaponics

Hi Y'all,
I'm trying to figure out a few things for my what seems like centuries long expansion....

The sump has been running and grow bed above it have been running as a simple flood and drain system with around 320 cf of wet media for a few months now. The other grow beds are built, giving around 960 cubic feet of media overall. Tanks are more or less in place.

One thing I'm wondering about is growbed pre filters.
I currently run a rff on a different system, and it does settle a lot of solids.


I was thinking of having two tanks go into one rff and then into a mbbr before the grow beds.


Are there any considerations for this setup?

I was able to pick up some k1 type media from someone on Craigslist for a great deal, so was wanting to use this in the system.

Right now the tanks are set up for 2 inch slo's. One of them has a 2 inch outlet built into the top of the tank at the height I'd like already. I have 2 inch uniseals, and drilled the other tank for it.

I'm running a 2 inch SLO on the IBC system, with a 790 gph pump I believe. It's been functioning reasonably.

I think the pump in the setup at question is capable of something close to 1200-1300 gph at the head it will have. The overall water volume will be around 1200-1300 gallons with the two tanks and the sump. I am planning on aeration in the ft, in the sump, and in part of the gb. I have it split into half constant flood and half flood n drain. I put slotted tubes into the constant flood side. So it might not turn over the full volume in an hour. But, hopefully the aeration will make up for it.

Now, logically, i always read up about stuff after I start things. So, It looks like a lot of people use 3 inch to 4 inch pipes for SLO's. But this is also based on flow rates, yes?

Should it work in theory?

I know the rff functions better with a certain flow rate.

I can't remember the max flow rate of the pump I'm running a the moment, but it is variable speed jebao, and it's currently going to one grow bed from the sump. It's running on low speed, and has a decent flow.

I was thinking of piping this to the two tanks, and splitting the flow to both, then having them exit into the rff, from here, possibly split to all grow beds, to the sump. The downside of this, is that a pipe would block the open flow of the path between the grow beds.

Right now, I think the overall slope of the ft exit plumbing will have about a 3 inch drop along the length of bs.
if it's set up in one long run, cutting across the path between the gb's.

I was considering dropping the flow to the sump just to keep the walkway between grown beds open. This could be from the first grow beds by the fish tank to the sump, then pumped on the return from the sump with a split to the last gb, and back to the ft's. I might end up needing a more powerful pump?

Right now, the grow beds are in place, I'm trying to level the tanks, and would like to figure out a pre-filter setup.

Right now, I feel like it's coming together, but I feel lost at the same time......It's out of my comfort zone for sure, especially mbbr's and flow rates....But, then again, how does one grow?????

I know I rambled a bit. These things have been creating a block for me. I truly admire people who can get to the point.....alas, it is not one of my strengths! Any ideas or thoughts are welcome!

Hi mate, 90mm is often used for the SLO as it’s stormwater pipe (cheaper) will take a large volume and a smaller pipe can be inserted in the upright to increase the flow by reducing the volume which will increase the velocity.
Is one of the gbs going to be a raft bed? I’m guessing the gb to the left is?
You need to look at overflow failure when planning, will 2” pipe be large enough to cope with the flow? I have 2” pipe between my sumps and it’s too small for my flow rate which is a pain as I need to meter my flow.
It’s always easier to reduce.
I’d split the flow from the filters to the gbs as per your first dwg.
All my pipe work goes underground giving me access around the beds but have a 12” height difference, I’m not sure you can do that unless you use large pipe. If I used your 2nd sketch the gravel bed would be the pump fed bed.
Now who’s rambling.
Does this make sense?

Hey Skeg!

I have a bunch of 50 mm pipe laying around, as I got it when a local hardware store went out of business at 60-75% off. Which is part of the reason I wanted to go with it.

The only part that I didn't quite get was the smaller pipe inserted in the upright bit.

So would that be like a 50 mm upright, with the rest being 90 mm pipes? The 50 would increase velocity, and it would dump into the 90? 50 to 90 at the "T"?

I currently have the one on the left running as a mixed media (Pumice, hydroton, scoria), and was planning on running all media for now.

I like the idea of dwc, and it looks like some people have really good success with it, but I will just be running media for now. I could potentially expand to the other side of the tanks in the future, but it would be pushing further into rat and Opossum territory....I do have one fancy styrofoam board (beaver board)...

The reason I want the mbbr is to help with high stocking rates...and high ammonia...Maybe the k1 would be better used for a different method of filtration like Scotty's static up flow??? Maybe I have enough for both?

My understanding is that a mbbr increases bio surface area, mainly helping with the ammonia conversion, and the up flow removes solids... I already have added a cone into the rff barrel.

I wouldn't have to go underground if I were to keep the opening/ walkway between grow beds. I built a deck a few months ago, and can extend the deck to cover the pipes if they empty to the sump.

Hi mate, no the smaller pipe reduces the larger pips volume and this allows less flow which in turn raises the head of water or water level in the tank while still maintaining a larger surface area.
The smaller pipe inside the 90 riser can be removed or swapped out for another size easily if required.

It’s a shame this forums contributor base has dwindled there used to be a great knowledge base who could answer questions far more eloquently than me!

So it's inside the riser pipe. Looking back, you clearly said that the first time! LOL

I'm thinking that's it. Snug fitting inside, which will increase the velocity, but it's removable if necessary.

I am coming to be much more of a visual learner these days. Do you run a tank like this? Pics?

I actually found a bunch of forgotten 3 inch pipe under all my other pipes. It's 30-40 ft.
But, here in the US, things are kind of tricky with pipe sizes, at least from my experience. Things don't fit sometimes, even though they seem like they should...

This is 3 inch poly pipe, meant for drainage. All the fittings I have found that are close in size fit it loosely, and it is thin walled pipe. Maybe that's why?

I just checked it against a 3 inch uniseall, and it fits loose too. I can't remember if all pipes fit uniseals loosely until they are put into the proper size hole, and they snug up. It's been a while since my last install.

I know what you mean about the forum. I stumbled across the forum when it was super active, probably 8 years ago or so, maybe 9. The exchange of ideas was inspiring and got me hooked. That's when I should have built my system!!

But, it is what it is, and I'm happy to get feedback when I do...

I use a standard SLO, 90mm in my tank with 20mm holes in the base which has worked well except for when the fingerlings snuck out. Now I have a second smaller tank connected with a 40mm SLO with 10mm holes for fingerlings.
I’ve found that you can connect pressure pipe to DWV pipe but you need to be constructive using fittings differently to their design like using the outside instead of the socket. A bit of playing in the hardware store to figure out the combination. I have 90mm a DWV header teeing and reducing to 40 DWV feed to gbs then to a 25mm pressure riser at each bed, this also seems to work well as when the pipe work reduces the velocity increases forcing the solids to the beds and have valves at the lowest point to purge if required.

I've had some fun trying to make some crazy ideas work in the plumbing section.
These days, I try to get in and out as quickly as possible.
Unfortunately, these days, it's hard to find workers in a lot of the big box stores who even know what they sell or where to find it.
Every once in a while though, you find a gem who is willing to play along, and get creative to help you solve a creative plumbing issue....