Backyard Aquaponics
A place to discuss aquaponics

Cool - thats how I pictured it.

I tried one with some clear PVC tube that I bought for that purpose, however the venturi just filled with water?

Does the venturi need to be at the highest point in the line - ie. as high, or higher than the outlet?


BTx

Bluethumb,

The venturi is the highest point in my system. Didn't really think about it before hand but I guess that make sense. However it is pressurized water so I'm not sure. The only time water comes up the breather for me is for about a second after I first turn on the pump before the flow starts to draw the air down. Might try it down at my sump level as an experiment and let you know.

My venturi (same Style as Hillsy) is at the bottom of the system (4 metres below delivery point to the GB) and works fine. It's the amount of pressure differential in the Venturi chamber that determines if air is drawn in, or water goes up the tube. Make sure that you have a "constriction - expansion - air intake at that expansion".

Cheers IanK

BlueThumb,

I tried the venturi down at the sump level and it still worked fine. So height isn't a factor in its operation. Maybe your tube wasn't restricting the flow enough to cause the suction. As I said mine fills with water for a second when first turned on, until the flow is enough to cause the suction then it works great.

Cheers for the roadtest - good to know.

I think I need to redesign mine - it's basically a 19mm to 13mm reducer T with some 6mm clear PVC in the T as the air inlet. What did you use to bond it?

BlueThumb,

My T piece is a 25-19mm reducer and the 16mm electrical flexible conduit I used as the air tube was a tight fit. I just put a bit of PVC glue around the top to stop the slow dribble coming out but yeah silicon would have done the trick.

Really neat work with the window, will really be a cool sight once the fish get bold enough.

How did you connect the bell siphons to the drains in the bathtubs? did you remove the original fitting altogether?

Hi Abdul,

I used the standard bath fittings, down into 40mm plumbing pipe with a screwed adapter all from the plumbing section at Bunnings. Have since found that BYAP actually stock the threaded adapters that fit 40mm retic pipe which would have been a lot better. Bigger internal diameter and standard bends etc. The plumbing stuff is a fair bit smaller and has elbows and T's at 85 degrees for drainage instead of the 90 degrees for the pressurized pipes. All part of the learning curve.

As for the siphon. At the base of the stand pipe is a 25-20 reducing coupling which fits down nicely into the bath drain. The bell and strainer simply sit on the bottom of the bath.

Cheers :]

very nice, very tidy system one question, how many L of GB do you have with the baths??? any idea?
im just wondering if youll have enough to filter the water when your SP get bigger.

i tried SP/ trout, no deal. the SP got munched . . .

Freoboy,

I have about 700L of grow beds + the small bio filter with another bath on the way which will take it up to about 900L.

perfect

Hillsy I did a venturi syst. putting a 15mm end cap upside down into a 25mm plain T drilled a large hole in it on the exit side then put a piece of 25 mm pipe behind it got it running off the drain sunk the drain to the bottom of the FT and getting an awesome stream of bubbles every time it dumps, will see it when I take photo's I haven't glued it so I can pull it apart to show, problem is, got to brand specific with the end cap I have three brands on the shelf, dura, iplex and holman, I'm pretty sure it was the Dura that fit like a sock, will double check when I take photo's. Just being a show off, hahaha lol

Yep, got all sorts of brands on my shelf too.... just never found the need to show off... my end cap...