Backyard Aquaponics
A place to discuss aquaponics

I have 330gals FT with 2 GBs. And 100gal sump and 15gal radial filter. ( thinking about adding a baffled filter to get more solids out )
For my SLO I've been using 1 1/4in pipe in this order. FT to radial flow to GBs. I've had this setup for about 8months now. It works fine but I'm noticing when I try to add a Venturi it slows down my water flow and thus causing problems with my siphons not shutting off. I've tried upgrading from a 620gph pump to a 3000gph but the larger pump even with it turned down over flows my FT. So Venturis are out of the question.

My question to you guys is , for over all better performance of my system, for the setup that I have do I need to upgrade my SLO to maybe 2in ?
If so do I run 2in all the way around through the filters and into my GBs?

I don't think there has been any trials or tests done regarding optimal SLO size. The general consensus is the bigger the better.

Too big and it wont lift larger solids, too small and the FT overflows.

However, 32mm is way too small for a 3000gph pump (even small US gallons)!

Have you considered just ditching the siphons and running Constant Flood?

Other than enlarging the SLO, you could also go to something along the lines of a Cornell dual drain setup with the higher capacity pump.

But I have the pump turned down with valves.
Like I said its not a problem until I try and hookup a Venturi or increase the water flow

As troublesome the siphons are I really enjoy watching and hearing them.

And you learn little tricks to make their operation more reliable...
....

Buidoi, that's my whole goal
Just trying to fine tune everything, to get better performance and water quality.

I've got 1 1/2 inch (32 mili) SLO pipe. Yes, it is too small. And my system (FT) is 2600 gallons. I've built with cement, so I don't have a lot of choice. I now have a 200 micron sock filter on the overflow. It catches an amazing amount of gunk. It would have been far better to run it all through the RFF MBBR combo. Only good thing about it is the retention time in the MBBR is longer because of the small SLO.

I don't have any experience with MBBRs since I have 2 GBs do I need one?

I've herd nothing but great things about the Sock filters, plus they are really cheap. I've even herd of people using a 200micron sock for a few days then change it out with a 100 micron sock with amazing results.

Far as my setup if 1 1/4 is too small do you think I should up grade up at least 1 1/2 since I only have 330gal Ft?
If so do I just run the 1 1/2 pvc from the SLO through my filters then GBs?

I wasn't saying I know diddly about fluid dynamics, although I may have made it sound like I do, sorry. There are plenty of people who do know what will work on a smaller system. I did a moving bed bio-filter because I wanted to raise my fish stocking density, which we did not and I'm glad of it. One of the cool things about the RFF is you can see what is coming up through the SLO and if it is working. Another thing I didn't snap to, which became apparent after our trout fry started growing is the quantity of poop the SLO needs to move. I think this is why you'll hear that your 1 1/4 inch pipe is too small. At some point the pipe can be too big as well to effectively raise poo particles. All I am saying is with your setup you can change it later, right? Just try what you have. You'll see if it is working. Or go up to two inch and try that. Hope this helps

I would run at least a 2" SLO on a 300 gallon IBC.

Would you run 2in all the way through the radial flow and baffle then to GBs?