Backyard Aquaponics
A place to discuss aquaponics

Pretty fish!

Do you put a bit of oil on the grill tray before the fish go in?
yes nice looking fish

Dan ,, 35 PSI air pressure on the injector nozzle ,, or water under 35 PSI presuure ,, sorry if I am missing what's happening.

If it is at the injector nozzle the contact time with the water is part of the efficiency ,,

Chappo, 35 psi water pressure. The air is sucked in via venturi, and therefore there is no need for an air pump.

The fish are pretty,, pretty tasty

Ok... doing a little reverse engineering and I'm stuck. What is the black thing? Plug is definitely 120V. I'm assuming that this is what's used to pressurize the PVC pipe but I'm not sure. Any idea?

UV light?

I think you nailed it. Couldn't find a black one, but this one sure look similar.

http://www.americanairandwater.com/water/trojan-uv-water-special.htm

So then the water pump by itself provides enough pressure...

Yes its a UV light.

Ok I have some numbers to determine how much air I need inducted in. If Im wrong on any of this please let me know!

The industry standard says 100 pounds of tilapia need .03#, or 13.607 Grams, of Oxygen.

A cubic foot of air at standard temp and pressure is 20.99% oxygen. So I cubic foot of air contains 8.49 Grams of oxygen.

So to provide oxygen to 400 pounds of fish I need 52.268 grams of oxygen per hour which requires 6.16 cubic feet of air in 1 hour (if at 100% transfer efficiency).

Sorry about the grams/pounds/feet thing. The venturies are rated in cubic feet of air per hour, and Air and oxygen are rated in moles and grams..

So now I know at 7 gallons per min, 35 psi inducting 9 cubic feet of air per hour I should have plenty of oxygen and most if not all of should be absorbed quickly.

Now the question, do I make this up or down current flow water?

If up flow then the undissolved gasses will be pumped out, but contact time will be decreased. If down flow then I need a way to release the nitrogen from the tank/pipe. Do you think a standard tank float will work in a pressurized tank?

Oh, chappo, I talked to the aqutic eco ppl and they said the oxygen cone need pure oxygen in a down flow or it will build a nitrogen bubble to fill the container.

I guess shade cloth needs to be put up soon since temps are reaching up to 100° F (37.7 C) now. The algae is starting to get darker. I installed a 1/20 HP gast air pump on a 8 inch rubber diffuser and this morning that DO was 6. The .7 CFM air flow did make a difference. So it was worth slipping to the pond and going for a swim..

Got a question on reading these test. Do you stop adding drops when the color becomes a light blue or when the color is fully blue like on the "chart"?

Another tasty meal today.. One Fish 688 Grams and One 389 Grams. After deboneing the meat weighed 268 Grams; 24.8% of live weight.
The Fish


The Fish Cooked

Nice fish Dandi... very nice...

That looks like your tilapia... what kind Dan?

Looking good! Yum!

They are AP tilapia, but to be honest I have no idea what species. The off spring of the first batch were orange, white and black. The orange fish did not grow much or have a nice body shape so they were disposed of. The white fish do not eat as heartily or grow as fast and only a few grew large over the last year. Its these white/silver fish that we are eating. The black fish grow faster and eat like mad so I separated the black fish as I am using them as breeding stock.

I hickory smoked this last couple and the taste was very.. YUM!

Hickory smoked. Nice. You got a store-bought smoker or built it yourself?

Store bought, but I would like to build one. The store bought only last two years then you have to buy another.

I guess I need to build one before winter so I can smoke and vacuum pack all my tilapia this fall..