Backyard Aquaponics
A place to discuss aquaponics

Again, don't panic. You can hold off of feed for a while. You certainly have to be careful with trout. My tilapia handled over 10 ppt of nitrites. But then again they were born into a world of 44 ppt salinity with agricultural runoff as their main diet. 10 ppt nitrites probably seemed like paradise to them...

Thanks guys for the help ill salt it today an see what happens, will it affect veggies much

1ppt will have no effect on most vegies


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thanks bender, always good for advice, if your ever up bunbury way call in an have a lookse

okay so I've done a water test first thing an the results are

ph~6.8
ammonia~1.0ppm
nitrite~2.0ppm
nitrate~5.0ppm

ammonia has dropped from nearly 4.0ppm
and nitrites have stayed but nitrate has gone up on a reading
temps are 15

Yep - its handballing from left to right on the charts.

another week or 2?

thanks jayendra ill keep on watching, so still hold off feed you think

I would hold off until ammonia and nitrites are <1.


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thanks bender, i tried playing with a venturi today and I'm using 40mm pipe gravity fed to return water into tank so i used 6mm tube drilled through an elbow it works but not very well.
then i used a 19 mm piece of garden hose pushed into a t piece and it also works but not as good as i want it to, my problem being i don't have the pressure to put the bubbles out, I'm wondering if i use a bigger hose would this make more pressure or do i reduce my 40mm pipe down so it builds more pressure up but then I'm worried that it may build back pressure and not allow my grow beds to drain freely,

anyone got a good idea on how to solve this or maybe an idea thats worked for you

Never played around with venturis so I don't know. I'm sure others on here will pipe up. I think you need a large pump and a restriction for them to be effective


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yer my pump is big enough i think if i use a bigger hose it will reduce volume of water being able to get past which will help bubbles an pressure but ill see how i go

Hey Hezzy, instead of a Venturi for your drain you would be much better off fitting a spray bar on it.

Ok skeggly
That sounds interesting does that just need an end cap an some holes or an actual spray bar ,
Does it have same affect as the Venturi for airration

I have it on good authority that it is far better than venturis on low pressure piping and high pressure, (where venturis perform their best). Set it up however you think, you are just trying to make the water enter the ft with the most surface area for oxygen exchange. It's a bit noisier also but it lets you know all is well.

Spray Bar: I made one with plenty of 5mm holes on both sides and then an elbow at the end pointing at an angle for circular flow around the bed. My pump is big enough to push water through the holes and out the elbow - so I wouldn't put a cap on it if you don't have to as this will restrict the flow.

Venturi: yes reduce the pipe diameter down to create more suction
Venturi I made but have now changed to spray bar