Backyard Aquaponics
A place to discuss aquaponics

Hi All,

I am redesigning my system (within financial parameters ) to a CHIFT-PIST design. I have my fish tank higher than my garden beds and my sump (old FT) down below. I want to use a SLO from my FT, but not sure what size piping to use. My pump has a 25mm outlet, and I currently use 25mm piping throughout to feed 2 x 300L GB's, I intend on adding another 2 x 300L GBs.

Is 25mm too small for a SLO?
Is it worth going to 50mm pipe given the pump's outlet is only 25mm? I was only thinking of the pump to FT and SLO backbone @ 50mm, actual GB delivery lines would stay at 25mm.

Thanks in advance.

dustintheshelves.

90mm

Why's that Charlie?

Sorry I don't know much about the physics of it all, I'm guessing it doesn't matter that what goes in is less than what goes out (ie 25mm in and 50 or 90 out)?

Bigger is normally better for a SLO.

Even if 90mm is too large to start with, it will give you room to expand (should you ever want to).

Also, your pump will push water along the pipe (which you may want to immediately upsize from 25mm to 40mm to reduce friction), where the SLO will be relying on gravity. Ie a 25mm SLO will be slower than the rate your pump will be delivering water to your tank, causing it to overflow (or if the water level covers the T will siphon it - which isn't a bad thing either).

sorry mate should have explained, as Arbe so kindly mentioned - 90mm is a proven size for solids removal and your right that it doesnt matter what size piping your incoming water is, its more so that you need a friction free path for heavy solids to move through. You can step the 90mm down to 50 then 25 at the beds with ball valves which you can throttle to play with flows, obviously your incoming water volume will change your solid removal efficiency. Or you could run 2 x 50mm if you dont want to use a 90mm although it wouldnt be as efficient.

When it comes to SLO's - bigger is better

Thanks Charlie and Arbe. My system is only 1000L in the FT (750 in the ST), I'll probably only run 20 odd fish in the tank. I have 75mm pipe lying around, so I might compromise and use that. My next question is how do I plumb it through the fish tank wall?

You could use a Uniseal..


Juergen

I had thought about that Juergen, but I can't seem to find anyone in Adelaide who sells them, the Uniseal website says it's unavailable and I'm somewhat iffy buying it off ebay. My other option is a standard tank fitting for a rainwater tank.

The uniseal website still down - it was down when I wanted to order mine (almost 12 months ago).

I have sent you a PM of the details.

Thanks Arbe!

For anyone wanting uniseals and can't get them locally ring the number on the"coming soon" website and they will take an order over the phone. $30 minimum if paying by CC and they will send them out that day. They are having some problems signing up plumbing companies to stock them.

I got 3 90mm seals yesterday at $10.70 each (ex gst). I am clueless as to whether this was a good price or not, no-one else stocked them.

http://www.uniseal.com.au/

The service was great.

I got mine from Fresh By Design. They had two types for 90mm - one for $15 and the other for $6. I got the ones for $6 - got 7 of them in use, plus 4 x 40mm and 3 x 20mm. None of them have ever leaked and they are very easy to use/install (well getting 90mm pipe thru requires some muscle).

Postage was $5.50.

Note: pricing I am quoting is 12 months old.

Dustin, a trick on here with the 90mm Uniseal is to use some hot water with a little washing up detergent as they can be a B**ch to get through Worked for me.

I also run 25mm from my pump to my 1000lt FT with a 90mm SLO. It cleans up the bottom of the tank nicely and wouldn't go any smaller. It still needs a little 'head' above the SLO to get the water moving well so leave some room above the SLO outlet hole so it doesn't overflow out of the FT.

I used a little vegetable oil just to keep icky stuff out of my system. Slipped right in!