Backyard Aquaponics
A place to discuss aquaponics

Thanks Jaymie.

Do you have a rough guestimate of the size your growbeds have grown to?

Hi Mylesau, my Silver Perch (150), platys (100s), goldfish (10) and koi are happily swimming in my 75000 litre converted swimming pool. I have one 250W pump which pumps 3500 litres per hour to 2metres from which it flows into six growbeds and ponds. The water is healthy, clear and fit to swim as well. You can see a pic on http://www.backyardaquaponics.com/forum ... ht=#104072

How much lift can you get using an airlift? Are there any examples/pics of this working?

My block slopes down towards the tank a little, but I don't think it would be enough to allow me to put the growbeds high enough. Digging is not really an option.

Yep this is what I'm thinking will be the best/easiest method. Though I'd hope the poop can be 'pushed' up using a standpipe and upflow generated from the return from the sump tank.

Great stuff adrian. Gives me confidence in it all working.

Are you running that pump 24/7? I don't want to use anywhere near that sort of power. But then I don't have anywhere near that sort of volume.

Place your growbeds on blocks/stand to a height of about 80-100cm... makes harvesting and things easier....

Would that height plus the slope of the ground give you enough?

Go for a good pump with a sump tank then, good pumps are more efficient than airlifts and work better. Anyway buy a good one and it will last longer than you. Get a good timer too. Drill a hole on the bottom side of tank and have piping coming upwards and overflowing in the growbeds at the height you need it to.Check EB's system they are very simple and easy to play with.

Electric pumps are far more efficient than airlift pumps.
Your striving for reduced power consumption is good, take the advice above and use a small pump (100W should be OK to turn over the volume of the GB every hour).
My 5KL FT is using a 50W kiddie pool filter/pump as a GB flood pump and it fills ~1000L of GB in 10 - 12 minutes every hour, then overflows to the sump.
I have a 750W sump pump to return the water to the FT.

GO for it!

I really don't thinks so, unless I put them in the neighbours backyard

I do like the idea of the airlift though, even if it's just helping to draw up the poo and aerate the tank, though I don't think that should be a big problem with the surface area and likely low stocking rate...

Surface area will not aerate without the surface tension being broken by falling water.

If you have fresh food in garden you can reduce size of fridge which will be significantly reducing power consumption compared to a water pump.
A fridge is at least 1 KW compared to a 250 W of pump, other wise use standpipes and put a timer to flood the growbeds in 5 min every hour, big pump so big investment but small consumption.

We all ask ourselves how to reduce the power demand of our systems here, that is a major thought of BYAP.

and far more likely to suffer from stratering (sp?) of DO and temp.

mylesau - I agree with most that is said. Why not use the big one. More stable. Where are you getting the damaged small tanks from - if you have a source, PM me :-). I'm looking for something I can put below my setup (on a lower lying part of the block) to act as a sump.

Yes, I run the pump 24/7. Likely as not, I could get away with less.

Yep, will be returning water from the sump and splashing it in. I'll probably add a venturi to pull in a little more air as well.

I've been looking at these:

Oxygen Saturators

and these:

Oxygen Cones

thinking I might be able to incorporate one if I can find a small air pump that I can run of solar/battery.

But I don't think I will need it - perhaps as a backup only?

With your low stocking densities, you would probably be better (especially from a power consumption viewpoint) just running a small fountain pump either as a fountain, or with a small venturi to get your DO levels up. The Oxygen cones and saturators are for places where you are using pure oxygen in an aquaculture environment.

You could use some of the same principles, but they use high-pressure inputs to achieve their ends.

If I were in your position, I would do one of a couple things:
Put the input for the GB pump in the center-bottom of your tank and
1- use a small pond/fountain pump or aquarium power head to break the surface tension pointed parallel with the side of the tank. This will give you a slight swirling effect to get the sediment to the bottom center of the tank.
2- mount an airstone half-way down the tank in the center. This will keep the top of the water moving, and give you a torroidal flow, also getting the sediment to collect in the center of the FT.
3- Do both. We don't need millions of liters of water being pumped to get 14KL of tank water moving.