Backyard Aquaponics
A place to discuss aquaponics

Hi everyone! First off, GREAT forum! I can't say enough about the knowledge base and experts here. I've been researching as much as possible and am now ready to get things underway. I wanted to post my ideas in case there are any concerns or adjustments that I should consider...so please feel free to offer feedback!

What I currently have...

350 gallon spa for fishtank
(2) 50 gallon 31"x41"x18" grow beds
(1) 60 gallon 3'x6'x7" grow bed
100' of black irrigation tubing

I was planning on building a platform for the two 50 gallon grow beds to go over the back of the spa. These would be media grow beds. I planned on having the media beds drain into the 60 gallon bed that I would turn into a raft system over the front of the spa. This would drain back to the fishtank. I'm trying to avoid a system with a sump.

What I'm considering...

Using a RIO 20HF pump (1290gph, 990gph with 4' lift, 60 watts)
Media = Bed filled 2/3 with 3/4" crushed granite and topped with 1/3 hydroton
Leaning towards running the pump 24/7 with bell siphons in the media beds

Here are a few questions for anyone willing to offer their 2 cents...

1) I know the gph per tank rule of thumb, but can a pump be TOO big for the system? I am even considering the Rio 26HF (1350gph with 4ft lift, 100 watts) since I have an extra 50 gallon grow bed and 60 gallon grow bed tray that I might want to add to the system at some point. In the meantime I could just redirect some of the flow from the pump to help circulate the fishtank right? Or is this WAY to much juice for a 350 gallon fishtank?

2) I know you can't fight gravity, but is it ok if the plumbing from the media beds to the raft bed is level? Or does the raft bed need to be lower. Would a bell siphon or loop siphon be better in this scenario? AND would the bell siphon or loop siphon create enough pressure to drive the water to the raft bed if it was 1-3" higher?

3) I'm leaning towards a bell siphon and leaving the pump on 24/7. I did see in a few forums that RIO pumps were not good with timers. I didn't see any specific info that would support this. Does anyone have any first hand experience or info on why this would be the case? If I ever decided to use a timer based system instead this would be another argument for the bigger pump.

4) With two 50 gallon media beds draining into a 60 gallon raft bed, would I still need an air pump for the raft? I'm thinking so, but thought I'd see if anyone has any first hand experience.

I've included some basic sketches...one of the top view, and one 3D...I'm slightly embarrassed with the work but figured this was better than nothing.

Thanks for any feedback and thoughts!!!

Well...

1) yes that sounds like a lot of water flow. You will be able to cut a line back in to the FT but that might cause to much flow for the fish. If you need to slow down the pump just have it run up a 8' tall PVC line then back into the FT. (But typically I like an overpowered pump... but this looks like a lot)

2) No. If you wanted to have a CF system then you will be able to get away with a better flow, but you want to have a natural gravity flow, not pressure, because if you have a blockage... it will not just be an overflow it will be a blow out! But, you could pick up the height form leaving your FT lower then max. This will allow for the extra depth and flow.

3) No comment, I prefer siphons for media beds and CF for DWC...

4) If you are only having "lite" fish densities then you will be fine... especially because you have a large pump blowing back into the FT. Just make sure you leave an air break before hitting the FT (Do not submerge the pump line into the FT)

Thanks CJ for the time to reply!

It sounds like the 990gph pump is a bit overkill as it is, but it gives me some flexibility for future additions...I kinda new the 1350gph was a little unnecessary but the 2nd opinion always helps.

Hi CJ-California

Just a question on your reply.

What is wrong with having the water pipe from the pump submerged in the fish tank?

Regards
Matthew

I figured this post is due for an update...

After a very dry and rather warm winter I was all ready to get started on the AP project and the rain came. I've had to be patient but things are slowly starting to come together.

To have better access to the growbeds and fishtank, I'm building a deck around the spa. The dogs seem to love it!

Now it's time to build the grow bed support and build some bell siphons. We have a local fish hatchery that is only open to the public once a month. Unfortunately their public event is tomorrow so I'll need to wait until next month. I'm hoping to get a lot done this weekend so the system has time to cycle before April's public sale. Fingers crossed!

Nice start. I'm nearby (Granite Bay) and getting a complicated (only 'cause I like to complicate things ) system started. My son likes to build stuff and is really excited seeing the progress. Fish-less cycling at the moment while I perfect the water flow. Will be following your system, too.

Hi John, nice looking setup. We'll see how these systems take the heat! Looking forward to more updates and cycling the system.

So as not to siphon your ft water I'd imagine.

I'm running into a design challenge, and I was hoping to get a little feedback.

My goal was to have 2 growbeds that drained/filtered into a raft bed. I was planning on using bell siphons to drain the beds and pvc run to the raft bed with a small drain...YES I knew there would be some finetuning, and I wasn't quite sure how the pipe running to the raft bed would affect the siphons.

SO, just in case my design idea didn't quite work with the bell siphons, I decided to only have ONE bed draining to the raft bed instead of both. Initially I thought I could just connect the media bed and raft bed using straight PVC and some uniseals. But uniseals are a pain in the butt! I think I can manage them with the bell siphon outlet, but I don't think it's realistic any more to use them to connect the two beds unless I fit 2 pipes individually and have a connector rather than one straight pipe for both.

I know I could just go back to the simple bell siphon beds, but I really like the idea of at least TRYING to incorporate a raft bed too.

So a few questions...

1) Does anyone see a better way to send filtered water from the media grow beds to the raft bed? Either scratching the 2" PVC and uniseal connection altogether or incorporating it in some new way?

2) I could work with the my original idea, but I don't want to ruin a grow bed if I can avoid it. Do you see any problems having a bell siphon, AND a 2" PVC pipe angling down to the raft bed?

THANKS for any thoughts, ideas, or suggestions. This project has taken much longer than I originally thought it would (YA, I know I'm not alone)...and I'd really like the plumbing to get finished soon so I can start cycling some H20.

Thanks!

Here are some pics if it helps...

SS,

From my trial-and-errors, looking at your latest pictures, I don't see how a bell siphon will work. There is not enough drop from below your GB to the raft bed. I think you will need to drop the raft bed at least a foot to get the siphons to draw. Also, where the 2" pipe enters the raft bed - is that the uniseal feeding INTO the bed or is that the drain back to the FT?

If it were me (to make it simple and save a few bucks), I would just drop a pipe through the top corner of the raft bed and deliver the water that way, cutting a hole in the foam mat.

For flexibility, I would plumb with the intention of both GBs feeding the raft with Ts to send water back to the FT. Put some ball valves on each leg and you can balance as necessary.

Another option is to have the bells drop to the fish tank and a valved line going from the GBs to the rafts. The water feeding the GBs will need to be sufficient to feed the rafts AND trigger the bells. The downside is you will need two penetrations per GB. I have had good luck just using 2" threaded fitting and a rubber gasket (get them from plastic barrels bung plugs). Just be sure to use Teflon tape so you can snug the threaded fitting up tight. PVC on PVC tends to bind/stick.

Hi John,

THANKS for the comments and ideas. I think we're pretty much on the same page...

I was planning on having the bell siphons drop into the spa below. Then have a 2" pipe continously feeding the raft bed from the side. I have a pretty powerful pump and was hoping this would work and with a small drain in the raft bed I was "hoping" the pressure (with some fine tuning) would be enough to be okay. Originally I was thinking of having the siphons drain to the raft bed, but that would just put the media bed up to high for me. I was also going to have some ball valves for each bed so I can adjust things.

I like your idea about dropping a pipe over the raft bed. Do you think that an outlet from the media bed halfway up and a drop into the raft bed would work? Another option would be to have a slight angle down from the media bed to the grow bed using the current uniseal feeding INTO the media bed.

I guess you can always learn by trial and error, I was just wondering if the idea of having a 2" piped outlet from the media bed to the grow bed would...

A) Just make a mess and have the raft bed overflow no matter how it is adjusted.
B) Totally mess up the pressure for the bell siphon to be effective.

Still thinking things through.

Hiya sacto, any penetration in the gb needs a media guard and will be prone to roots and more work.
As there is a hole already in the raft bed I would utilise it. I would raise the gb's 4" and run constant flood or timed flood n drain in the gb's using a drain fitting and standpipe with the drains emptying into the pipe to the raft bed or similar.

Thank you Skeggley. I was trying to keep the taller media beds as low as possible for ease of access, but it sounds like raising them and emptying into the raft bed is really the solution.

After the rain stops, we'll see how it goes.

Thanks!