Backyard Aquaponics
A place to discuss aquaponics

I have one for the SLO and the other 6 are to connect the 4 200 litre tubs I have as a sump.

Ah! I guess this is the answer I am looking for. I am planning to build my first system. a Chift Pist. I am bit concerned with the pump inside the tank as I have changed several pumps over time in my pond (because when I built it, I have no idea about drains!) because the fish poo and some other objects gets stuck inside the motor. nice!

Good tip.
I also found the tapering and slots works great. Also a smear of coco it oil worked 20% better.

I did end up using a jigsaw to taper the end a tad bit which was probably the ticket

Hi
I think I understand the concept but wondering what purpose the t-piece serves? Is the open end of the t supposed to be above the high water mark or underwater?
Thanks

Above so that if the pump stops your FT doesn't siphon empty.

Ahhh... so when the pump is working, the water will flow over the open end of the t, causing the SLO flow to start. But if the pump stops, the SLO flow will continue until the t opens the air again, then stop. Thereby saving the fish. Right?

Nope. It is purely there to stop a syphon. A SLO purpose is to draw water from the bottom of the tank and flow to its destination, if there is no T at the top it will syphon due to the water flow.

Imagine having an elbow ... but with a hole in the top.
If you didn't have the T piece then it would create a siphon effect and empty your fish tank when the power goes off.
Water can go up then down in this situation.
So in the pic below the air getting in the pipe stops the siphon effect.

The 't' also works as an overflow in case the suction holes at the bottom of the slo get blocked so it should be below the top of the ft.

Thanks everyone. Has finally clicked inside my head.

7 months later... having to rush to complete my second system before trout come! Is it a simple as having the bottom of the pipe touching the bottom of the FT that stops the fingerlings getting in?

Personally I think they should be called BLO's (bottom lifting overflow) as the primary purpose is to ensure that the FT water is properly circulated.

Then again I think RFF's should be called contra flow filters, Radial flow doesn't make a lot of sense.

Lunchguy you have a choice between slots, notches or raising the pipe enough above the FT bottom to allow the water to enter but not the fingerlings.

However after a few beers I can become slightly opinionated, in a happy way.

Thanks Sleepe! Hope you enjoyed the beer :-)

What causes the SLO or Venturi Drain to suck/vacuum the solids from the bottom of the tank ?

Is there a way to increase or reduce this vacuum effect (i.e. bigger pipe or . . . .) ?

IF (Assumption) the SLO is draining from a Fish Tank into a Radial Flow Filter
That would imply coming out near the top of the Fish tank dropping down to the bottom of the radial flow filter
then back up inside the radial flow filter (stopping at the input part of the filter)

Would it not be better to just come from the bottom of the Fish tank straight into the bottom of the filter
and then just come up the filter ? Or would this "break" the vacuum effect ?

Thanks in advance